Transmission:Automatic                                                                              FAQ Home

Volvo Maintenance FAQ for 7xx/9xx/90 Cars                                                                                                                     Version 5.0

In-Line Filters

Fluid Flush 

A/T Fluid Needs Changing; Late or Poor Shift Quality

ZF22 Transmission Fluid Drain

OD Switch Repair

OD Relay

Auto Trans Overdrive Problems: Solenoid

AW-71 Overdrive Malfunction: Fluid Blockage

Transmission Output Shaft Bushing

AW-70/71 Hard Shifts

A/T Won't Upshift

Kick-Down Cable Adjustment

Kick-Down Cable Replacement

Transmission Not Shifting Out of Park

Automatic Shifter is Loose

Auto Tranny Refuses to Reverse: Bad Mounting

AW-70L Transmission Life

AW-70 Maintenance: Bands?

Seal Leakage in AW70L Transmission

Stripped Trans Drain Plug

Transmission Line Crack Prevention

Turbo Lockup Torque Converter Function

ZF22 Damage in Park During Smog Test

ZF22 Fails; Swap for AW?

960 With AW-30/40 Has Busy Shift: Electrical Glitches

On-Board Diagnostic Codes for AW-30-40 Series Automatic Transmissions 

In-Line Filters. I've had one for a year and due for a replacement and "surgery" next year. But my unit is made by Tekonsha (#4350A.) It is call "MagFilter" and goes in the A/T return line. In addition it has a very strong magnet ring inside, you stick a nail to the plastic cover and it will hold it. Should be replaced every 15K to 20K mi. and it's about $28Cdn. I've been running with this setup in -36F (-38C) no problems. It filters down to 30 microns. For more info call Tekonsha 800-325-5860 (for your local distributor) [Note: IPD now sells this filter for both A/T and P/S line applications; Wix sells the same unit under their label.] After I changed it I opened the used one. I found that the magnet inside was foul with metallic particles (it looked like grease, because the metal dust was mixed with ATF).
Return line: The top line is the return line. You can check it by connecting a hose to the end from radiator (disconnect the "+" wire on the ignition coil) and try to start the car, you'll see ATF coming out of the line on radiator end. [Another note:] Hurst now makes a filter unit that splices into the transmission fluid lines. It uses a Fram oil filter as the filtering element.

Fluid Flush. I recently changed the trans. fluid in our '92 940 using the cooler line disconnect technique. There are apparently a couple of variations of the method:

My Haynes manual outlines the following steps (from memory, so they may not be *exactly* so, but it's close)

Here is another variant for the driveway or garage: I followed the return line back from the trans to the radiator and disconnected it at the radiator - it was the upper of the two lines at the radiator. I connected a clear plastic tube to the radiator fitting and down to a gallon milk jug marked with 1 qt marks on the sides.  I used the engine to drain out the fluid (not the starter - the fluid does not drain out all that fast - ~25 seconds for 2 qts - and stops as soon as the engine is shut off - so if you limit it to 2 qts at a time I'm pretty sure you don't hurt anything). [Variation: as the jugs fill up, refill with the quantity drained without stopping the engine.]  Also, I performed the drain - refill steps more than twice (I think I did it 5 times!) so that by the end the fluid that was draining out was *clearly* new fluid. (I figured that Dexron II oil is pretty cheap and a few extra quarts are worth it to ensure that I get a proper flush - now if you want to use synthetic, it would certainly be more expensive to do what I did.)

Everything worked very well - the only pitfall was that I ended up overfilling the trans. a bit (~3/4 qt) - I think I must have been a little off every time I estimated I had drained 2 qts. So finally I had to pump all that out of the filler tube while checking the level - a bit of a hassle but not too bad. [Tip: if you overfill, just unscrew the pan bolt slightly and hold it while the fluid drips out to the quantity required.  Messy but easy.]

A/T Fluid Needs Changing; Late or Poor Shift Quality.
[Query:] The  drive gear engages late when shifting from P to D in my auto transmission.  [Response: Marc]  The problem you describe can be attributed to either a low level of transmission fluid or a stuck valve body. If the fluid is low in the torque converter, it will take additional time to transfer the engine power to the transmission, as the power is transmitted through a fluid by spinning up a plate with fins on one side and the fluid spinning up a secondary plate with fins on the other (thus keeping fast changes in the engine power output from damaging the transmission).

I would recommend that, if you have not recently (within the last 6 months) changed the transmission fluid and transmission filter, you have this done. In my area, the change runs as low as $49.99 US, including parts & labor. If you have the Haynes manual for your car, take it with you if go to anyone other than the dealer, as the fluid may have to be drained in a non-standard way via a transmission fluid cooler return pipe (non-standard compared to other brands of vehicle). This service will also clear up most sticky valve bodies, as the new fluid reliquifies old gummy deposits...[Editor's note: see also Fluid Flush]

[Symptoms:]  Late or poor shift quality.  [Response 1:]  Since this is an unknown as to when the transmission was serviced I would recommend a power flush. Wynn's/Kendall has a machine that connects to the line to the cooler. Then they add a detergent and run the car for about 20 minutes with it off the floor and in different gears. Then they go from a recirculation mode to a change mode and add new fluid while discarding the old. This gives a full change including the torque converter. It will cost from $60 to $95 but I think it is well worth it about every 100000 miles with normal change in between. I think both my ZF and AW worked better and smoother afterwards.  Call around and you should be able to find some shop that does a power flush.
[Response 2:] How dirty was the fluid was when the transmission was finally serviced? Your transmission has no bands, just clutches. When pressures are right for a shift, fluid pressure is directed to the clutch(es) that is/are to lock up. If there is a lot of clearance due to wear in the clutch packs, you usually get a delayed and hard shift. If the valve body has a problem, it could cause reduced pressure to go to the clutch pack, causing a slip as it shifts.  The most common problem is governor pressure loss due to a worn output shaft bearing. Even after the output shaft bushing is replaced, the problem could still exist because while the bushing was bad, excessive wear to the transmission case where the shaft goes through, is common. A pressure test will in most cases will pinpoint the problem. This is reason # 71 for servicing the transmission at normal intervals. Every 20,000 miles is recommended. It's pressure test time.

ZF22 Transmission Fluid Drain. [Procedure:] ZF 4HP22 Transmission Fluid Change. This is passed along for the 740 owners with this transmission. I have the same transmission on my Peugeot and found out that if you leave the car for a few days on with the front end on jack stands, the fluid in the converter will slowly drip out. This way you can get an almost complete drain before refilling. [Maintenance Note:] There also seems to be a consensus by mechanics who work on this transmission that there is no advantage to using synthetic AT fluid (this question asked relative to the early failure problems from revving the engine with transmission in neutral). [Contrary Opinion:] I agree there is a problem with those trannies. You should know one more thing, HEAT is the biggest enemy of every tranny (especially in automatics). I've got one on my 740 and synthetic ATF dropped the tranny temperature from 92C to 60C (driving in a summer for about 40min. in a city). I've measured the temp. on the tranny metal line, the temp. of the fluid itself is most likely higher.

OD Switch Repair. My wife got excited by our new (old) 1988 745T, and managed to yank the gear shift knob clear off the shaft, with the OD switch wires dangling. The switch pushes out fairly easily and r&r was no problem; the wiring is a little tricky since it tends to jam (at least on mine) and make it difficult to properly seat the gear knob. I used electrical tape with a spot of grease smeared on the outside (I know, it's a solvent, but it prevents the wires from jamming), and the knob simply squeezed back into place.

OD Relay. [See Relay Locations for a detailed picture of relay location and removal instructions.]  [Symptom:]I have a friend with a '90 740 automatic and he is having intermittent OD problems that seem to be weather related. It won't go into OD when the weather is cold. Is the relay on the relay tray? If so, which one is it? [Diagnosis:] Yes it does sound like an OD relay. If I remember correctly on 740 it is by the Ashtray/FuseBox. It is pretty common component failure on the bricks. It will be a white Hella relay. Pretty simple to change. The relay is about $40-43 through Mail order from dealership. In my case I was "sure" it was the wiring, switch or solenoid, as the relay "looked" just fine. But as soon as I replaced the relay, all problems disappeared. The relay is about $40 from the dealer, or you can probably find it cheaper from a second appears to be a standard Hella relay.

[Response 2: Michael Daley]  I have just repaired the o/drive relay and rather than pay the UK£40 that the volvo dealer wanted for a new one, I took the top off the relay - all that was wrong with it was a cracked solder on the circuit board. Fixed with a soldering iron in 5 minutes, saving myself £40!!

For a more detailed discussion of relay repair, see Relay Repair vs. Replacement.

[Another OD Symptom:] I have a '93 940T with an AW71L transmission (or so I've been told...) Today I was driving on the  highway and it momentarily dropped out of overdrive into 3rd, at the time I was at minimal throttle. I dismissed that as a hiccup. An hour later (after making a couple of stops)I began driving and I noticed that the tranny would not go into OD, 3rd gear was the max. All of the other shifts are perfect. I tried pressing the OD cancel button a few times, and I checked the related fuses - no changes. Am I looking at replacing the overdrive solenoid on the tranny? If so, can anyone give me a part# and/or approx. price?  [Response: Abe Crombie] It is an AW71 no L. The turbos didn't get the locking torque converter feature. The trouble sounds like the typical OD relay failure. The relay is behind the ashtray in the fuse/relay panel. I believe it is white on that car and square in profile. The fuel system relay is the one to the left that is rectangular.

Auto Trans Overdrive Problems: Solenoid.  [Diagnosis: S. SteveSakiyama] There have been a few posts on autotrans overdrive problems (won't shift into 4th) when the brick is cold.  The problem disappears when the car warms up.  I posted my experience a month ago in response to another member who was having the same difficulty.  I'll repeat a summarized version here.
This applies to automatics, don't know about manuals.  I have an AW71 in my 85, 245 Ti.  When cold it would not go into 4th (OD) until the car had been driven for 10 minutes.  This would happen more and more frequently until it was a regular pattern.  Sick gut feelings (is a major repair needed?) usually accompanied this problem.  I checked/dealt with fluids, OD relay, wiring, and downshift cable but the ultimate problem was overdrive solenoid switch which sits on the tranny.  I bench tested it, and it seemed fine.  However an experienced tranny tech said "it just doesn't sound and feel right".  Replaced it with a used one (with the two inner o-rings), and the brick is fine.

AW-71 Overdrive Malfunction: Fluid Blockage.  [Query:]  I hope to find someone who understands the inner workings of the AW71 auto transmission. About a month ago, mine stopped shifting into 4th (overdrive). Once in a while it still works when fully warmed up but not always. I've replaced the OD relay with a new one but no change. I then pulled the OD solenoid which appears to be closed when not energized. I replaced the O-rings and reinstalled but no change. Before I buy a new solenoid, I would like to ask the following questions:
    1) Is the OD solenoid involved in the normal operation of the trans or does it merely allow the disabling of fourth gear via the switch on the shifter?
    2) When operating normally (OD not disabled) does fluid flow through the OD solenoid or is it blocked?
    3) When the solenoid is not energized, is it open (to fluid flow) or is it closed?
    4) Other than the OD solenoid, what could be causing my problem?
By the way, it's got 147K miles on the clock.
[Response 1: Scott] My first guess is the OD solenoid. The solenoid is naturally closed cutting off the fluid flow necessary for 4th gear. When energized OD on/light out the solenoid opens up and allows the trans to shift into 4th. The first test is to park in a quiet place open the drivers door and switch the OD on and off while listening for a click under the car. If you don't here it it is bad. If you do hear a click that does not necessarily mean it is good. Also check the wiring under the car to the solenoid. It tends to deteriorate near the shifter.  [Response 2:  Brian Oliver] I learned about the inner workings of the AW71 when we had this problem on our 87 740. It smelled too much like a control problem so I messed with the downshift cable (no effect), had the OD solenoid wiring checked (100%, oddly, as this is the typical culprit) and even took the car to a transmission shop, who suggested a valve body overhaul. New fluid and diddling the level had no effect.
Finally my wise old Volvo mechanic suggested that the plumbing internal to the solenoid unit, which has a right angle turn at the valve seat, could be plugging up. Problem: On my car the bolts may have been seized, and if one breaks then the transmission has to come off just to drill out the broken bolt. I took the chance, and half an hour later the solenoid unit was off, blown clear with compressed air (energized, I think, to open the passage) and reinstalled. The transmission worked perfectly.

Transmission Output Shaft BushingWhy Replace the Seal and Bushing?
...we replaced ours ('89 745) a few months ago, at approx. 115,000 miles. Why? I noticed that the output shaft was spraying a bit of oil onto the underside of the car... and my experience teaches me that such leaks only get worse, plus tailshaft play accelerates other wear.

Let me say that this is not necessarily bad or that you don't have an output bushing worn and a seal leak. First, when the bushing's worn, you usually get some driveshaft vibration, or"humming/drumming" in the car. So when the new bushing's in, it's noticeably quieter. (That was my experience on my '83 and '86 GL's, both receiving the bushing & seal at around 200k.)  Second, if the machined outer surface of the companion flange is worn where the seal rubs, there's a possibility of driving the seal 1/8" further into the housing so the new seal "sees" a fresh, non-worn surface. It all depends on how the original was mounted. You should try shaking the driveshaft radially at the transmission and see if there is any lateral movement...if you're unsure try shaking a known good one. Also, you can replace the seal yourself and leave the bushing will seal for awhile, perhaps a LONG while. Last point ...when replacing seals like these, check the metal part that the seal rubs against...if there is a notch you can catch your fingernail on you probably need to replace the metal part too...a rear axle pinion flange is easy but a driveshaft yoke you have to replace a U-joint, etc. (some people think U-joints are easy.)

This is part of what I'd refer to as preventative maintenance. I was quoted a price of $300-$350 to replace the seal/bushing. Bought the parts for about $45 (parts replaced were output shaft bushing, output shaft seal, rear housing gasket) and performed this operation myself in about 3 hrs, including setup/replace/cleanup time. Pulling the housing is relatively straightforward once the tranny's supported and the cross member and mount are removed. I believe that there are six bolts to remove and the housing's in your hand. Have a new gasket on hand and make sure that both mating surfaces are completely clean with no trace of the old gasket. You don't want to have to do this job a second time because of leaks.

[Another tale:] The tail housing removal is really pretty simple. I just finished replacing a transmission in my '89 744 project car. The tail housing was cracked and we initially hoped to replace only the housing, but Volvo wanted $253 for it and the junkyard had an entire AW70 for $400. Anyway the Dexron is still in my hair from finishing up the job, so my experience is as fresh as it gets.

Procedural Notes:
What you're going to do is take out the bolts that connect the output flange to the driveshaft, support the tranny and remove the rear transmission mounting bracket. Four bolts hold the tail housing to the rest of the transmission case.
[Procedure Notes 1:]
Start with the driveshaft bolts while the car is still on the ground. That way you can roll the car a little to get to all 4 bolts *easily*. If you're driving up on ramps like I did, this won't work and you'll need a crow's-foot wrench (my 9/16" worked fine) to get to the ones on the top of the flange. A generous supply of profanity helped in my case... It's a good idea to mark the output flange and shaft flange so you can mate them up when the time comes to put it back together [critical for proper driveshaft balance.] Once the bolts are out, push the driveshaft toward the rear of the car and it will pop out of the flange. You can shove it up above the flange to get it out of the way. Raise the car up (jackstands, ramps whatever)if it's not already and drain the tranny fluid. Put the selector in Park and use a socket to remove the bolt in the center of the flange. This bolt holds the flange to the output shaft. Once it's out you can pull the flange out of the housing. Remove the 15mm nut in the middle of the transmission mount (rear end of transmission). Support the case with a floor jack, just enough to take the pressure off the tranny mount. You should see the mount bolt come up slightly. Then remove the four bolts that hold the mount to the chassis. The mount will come off, and the tail housing will be clearly visible. Four bolts (14mm I think) hold the housing to the main body of the tranny. The top and bottom bolts are different lengths, so note where they came from. With a little "gentle persuasion," the housing will come off. On my particular car, the PO slid it into a ditch and caught the end of the center mount bolt which cracked the housing. This also saved me the trouble of taking off the "L" mounting bracket. It won't have to come off if you just plan to replace the seal. The seal is easy to get to and *looks* like you could pry it out with a screwdriver, but I have never tried this. You're going to end up with a roughly 6x6x8 inch housing which you can work on at your leisure.  If you don`t have the tools to remove/replace the bushing, you can just bring the housing to almost any auto service shop and they will be able to press a new one in for a few bucks.  Plan for about 2 hours under the car to get it out. If the gods of rusted bolts are on your side, it could be done in 45 minutes or so, I'd guess. Nothing is particularly difficult about the operation. Although I recently told someone to shoot me if I ever said it, "installation is the reverse of removal" (BOOM). See orientation notes below.  The center flange bolt only holds the flange to the shaft; no pre-tensioning or any of that other technical stuff.

[Procedural Notes from Bill Lauber:] VOLVO AW70 REAR BUSHING REPLACEMENT

Regarding Volvo Automatic transmission AW70 rear bushing  replacement ...I found significant play in the end shaft and proceeded to get the parts from my local Volvo dealer.  The bushing was quoted at $36 with the seal at $11 and the gasket for about $5.  I checked the yellow pages for a automatic transmission parts house .. found one and learned the following.  They carried every thing I needed, the only difference being I carried the parts out for a total including tax of $9.70.  A entire rebuild kit for the Volvo automatic was quoted at $108.00 and the dealer said the Volvo AW70 was one rebuild an individual could be successful with.  I have installed the bushing, seal and gasket and all is working well.


I used drive on ramps at the rear wheels not the front. This keeps excessive loss of ATF fluid when removing the rear housing.  HINT, with front wheels blocked from rolling, elevate one side of the rear all to allow rear wheel to spin on one side. This allow all to spin for easy access to drive shaft bolts as long as the transmission is in neutral and the emergency brake is off.

  1. Place support under Transmission pan that can be raised and lowered as needed  A board between the support and pan will help distribute the weight normally handled by the rear transmission support which has to be removed.
  2. Remove rear transmission support bolts from car frame and end of  transmission and remove cross member
  3. Disconnect speedometer hold down bolt at transmission then unscrew cable from transmission
  4. With transmission in neutral, disconnect end of drive shaft from transmission
  5. Insure transmission is in park
  6. Remove transmission shifter link’s rear pin ONLY allowing link to move out of the way
  7. Remove bolt from rear of shaft on transmission. Remember step 5 ... pull out shaft end
  8. Remove all 6 bolts holding rear housing
  9. Remove housing HERE COMES THE ATF!!... you may have to tap with block of wood to break loose from gasket. be gentle so not to crack the housing
  10. HARDEST STEP for me ... remove the old gasket material [Editor's Note: See Removing the Gasket]
  11. Punch out the old seal and bushing ... the seal was easy ... the bushing requires care not to crack the housing. You may want to have a machine shop remove and replace the bushing. I was successful but could just as well messed up at this point
  12. Install seal & bushing in housing [Editor's Note: See Bushing Orientation]
  13. Install housing with new gasket and six bolts
  14. Insert shaft with some ATF on bearing, seal and shaft  Torque shaft bolt
  15. Hook up shift linkage
  16. Shift to transmission to neutral
  17. Install drive shaft and bolts spinning elevated rear wheel for easy bolt replacement
  18. Install speedometer cable
  19. Install cross member ... elevate transmission as required
  20. After removing car from ramps check ATF and add as needed.

[Another Procedural Note from Don Foster:]

The parts you'll need are: new bushing; new seal; new gasket. In general, the procedure is:

  1. Jack up the car -- from the rear may be preferable.
  2. [Editor's note: mark the flange and shaft for proper balanced re-assembly.Carefully mark the linkage placement before removing it from the side of the tailshaft housing.] Drop the driveshaft at the tranny -- I don't think it needs to be removed any further, only pulled aside.
  3. Remove the companion flange -- I used an air gun (with the tranny in park). Some purists among us will probably tell me how wrong that is -- but both cars logged at least 50k flawless miles since.
  4. Drop the crossmember -- you might want to support the tranny.
  5. Remove the speedo cable.
  6. Position a pan under the rear of the tranny -- some fluid might decide to get in your face. Transmission fluid will run out when you remove the piece the driveshaft was bolted to (flange?) as well as when you loosen the tailshaft housing so be prepared with a pan to catch it.
  7. I think you need to remove the tranny mount bracket from the housing to gain access to the      housing bolts.
  8. Unbolt the housing from the tranny. Pull back gently -- a little tapping may be helpful.
  9. Knock the old seal out of the housing.
  10. Note the orientation of the old bushing as a reference for installing the new bushing.
  11. Examine the inside of the housing -- note there is a 1/4" gap, or opening, under the bushing, at the bottom of the housing into which you can cut.
  12. Using a hacksaw blade, cut through the old bushing into this opening.  Note the orientation of the original and align the new bushing the same way.
  13. "Peel" the old bushing inward and it'll pull right out.
  14. Scrape off any gasket material (most frustrating part of the job.) [Editor's Note: See  Removing the Gasket]
  15. Wash the housing, insuring that all chips are removed. [See Chip Removal]
  16. Be sure to prelube the new bushing and new seal before final assembly.  Position and orient the new bushing -- and using either a proper bushing/seal driver OR a socket of the correct diameter (perhaps with a 6" extension on it), drive the new bushing into position. I've found it slides into position easily, with only slight tapping from a hammer. [See Bushing Orientation]  [Tip from Randy:]  My automotive supply store has a full service machine shop and I never mess with this stuff- I take the tailshaft to them and have them press in the bushing. For the seal I apply a coating of grease to the outside diameter and tap it into place with a socket just slightly smaller than the diameter of the seal.
  17. Examine the new bushing to confirm the edge was not dented -- if so, clean it up slightly with a fine rat-tail file (and rewash). Be careful to not damage the main bearing surface of the bushing.
  18. Drive the new seal into position. I like to use a touch of Permatex aircraft gasket sealer, but it's not necessary.
  19. Clean any remaining gasket from the mating transmission surface.
  20. Install the new gasket. Again, I like to use a touch of gasket sealer, but it's not required.
  21. Lubricate the bushing and seal with ATF.
  22. Position, install, and tighten the housing.
  23. Wash the rear flange, lubricate the bearing and seal surface, and slide it over the splined tailshaft.
  24. Install and tighten the nut. I'm sure there is a proper procedure and torque.
  25. Install the speedo cable.
  26. Lift the tranny and install the mount bracket and crossmember. This might be a good time to install a new mount.
  27. Connect the driveshaft. [Editor's Note: 30 ft-lbs.]
  28. [Tip from Randy:]  On assembly be sure to bolt the linkages according to the marks you made before disassembly.
  29. Don't forget to check the transmission fluid level, particularly if you lost some during this work.
[Removing the Gasket: Randy] I've replaced two bushings and both times the most time consuming part of the job is removing the gasket between the transmission case and the rear housing from the transmission case. There isn't a lot of room to work your way around with the various tools to scrape the gasket off. I found a single edge razor blade worked best for me, and the second time I did it I was armed with a spray on gasket remover which helped a whole lot. Spray it on, let it soak, scrape a little.... repeat numerous times, being careful not to dig into the soft aluminum case when you become frustrated and begin to use that sharp wood chisel that always worked so well on removing gaskets from cast iron casings. Also it would probably be in your best interest to take extra pains to protect the exposed portion of the transmission from consuming the gasket pieces and various bits of underbody debris you will rub off with your arm- I wrapped mine in a clean rag (the rear of the transmission, not my arm)
[Chip Removal: Paul Seminara] Replace the bushing, when you do the rear seal.  Indeed the bushing will wear and sometimes the wear will be from small bits that wear the tailshaft flange as well. This is especially so on high milers. This usually will require replacement as well.

AW-71 Auto Trans Output Bushing Orientation Question.    [Query:] In replacing the auto trans output bushing, which way does the hole in the bushing go?  [Response: Patrick Petrella] I did get the bearing issue resolved. Ended up talking with a mechanic in Colorado, who seemed to know what he was talking about. Volvo was essentially no help. Someone sent me jpegs of two pages out of the Volvo trans shop manual, which clearly stated that the new bearings come with no hole in the side. I went back to the parts counter at Volvo and was shown that all their bearings HAD the side hole. A never-ending spiral of confusion.  So this Colorado mechanic said he had done this repair on many AW71 trans, and that the orientation of the side hole was not critical, but should NOT be lined up with either slot in the tailshaft housing. He puts the sleeve bearing in with the hole at the top. So that's what I did. I would like to know what the hole is for. Maybe used during manufacture of the bearing, with nothing to do with operation?

AW-70/71 Hard Shifts.  [Great Tip from Toni Arte]   The AW71 in my '86 740 used to shift very hard from 1st to 2nd gear. This shift is the first shift and it usually happens at about 20 km/h (depends on how hard you accelerate). It felt almost like getting rear-ended.  Nothing really helped. I tried to adjust the kick-down cable, change the fluid etc. Then I heard that this is a common problem on AW70 series transmission.
The real cause for this problem is a worn valve ball in the transmission valve body. This ball is the "15C" in the picture. This is a picture of the lower valve body. A replacement valve ball is available, you can order it from your local Volvo dealer. The part number is 1377746-1 (small blue valve ball).

In my case the 5.5 mm valve ball was worn to about 2 mm size. Note that the valve body can be accessed through the oil pan, so it's not necessary to drop the transmission.  A competent transmission shop should be able to change this ball. In my case the cost  was about $100, this includes two hours of labour, new gaskets and fluid.
[Tip from Gary De Francesco]  Rough 1 - 2 shifts are a possible sign of a worn rubber ball in the valve body that regulates how fast the various clutches and brakes are applied. As the ball wears, the fluid flow rates in some of these regulating passages can increase which will cause the various hydraulic actuators to engage faster.  This will feel like a sudden and rough engagement. On the one hand, with fast engagement, there is little chance for the clutches and brakes to slip. This means less wear, and hence a longer lasting tranny. On the other hand, these fast engagements result in a bit of jarring to the occupants of the car. The solution is to have the valve body serviced. This can usually be done without removing the tranny. So you have to decide. Can you live with a little jarring, or do you want to spend some money and see if it can be smoothed out.

A/T Won't Upshift. [Symptom:] If I accelerate very hard, I lose top gear, and as I slow down I lose each consecutive gear. I then have to almost redline the car before the transmission will upshift. [Fix:] The symptoms sound suspiciously like the transmission downshift cable is binding. It is not that uncommon on higher mileage AW70/71 transmissions. Oft times the binding is temperature dependent... The cable allows the valving within the automatic transmission to "know" the current throttle setting. It runs from the passenger side of the transmission up to the throttle "bobbin" on the engine (drivers side). The return spring is internal to the transmission and the cable is pulled out as the throttle is opened. If the cable binds, it will remain limp at part throttle... giving an incorrect signal to the transmission and making for prolonged operation in the lower gears. The cable is not all that expensive - approximately $75, and the labor charge is likely to be under 3 hours book time (FWIW, the first time I changed the cable myself it took 1.75 hours start to finish).

Kick-Down Cable Adjustment.
Function of Kickdown Cable.  [Discussion from Abe Crombie] The kickdown cable is used to regulate a pressure in the transmission valve body. This is called throttle pressure. The throttle pressure is effectively a pressure that "tells" shift valves in transmission how hard you are pushing the throttle and these shift valves now have a contest to see if governor pressure or throttle pressure is going to win. This pressure is also used to apply the clutches/brakes that engage a gear and the higher pressure goes along with higher engine power at higher throttle. Firmer shifts are a result of higher throttle pressure.  If throttle pressure wins the contest the trans remains in lower gear, if governor pressure wins the trans upshifts.  Governor pressure is directly related to driveshaft, and thus road speed.  If you tighten cable you increase throttle pressure and the whole shift point/road speed "map" goes higher.  If you loosen cable the shift point map moves lower.   The trans throttle cable (kickdown cable) also depresses a valve if you (or the throttle spool) pull the cable all the way out past that hard spot which is a detent to make you aware of the actual kickdown feature.  The kickdown valve increases the throttle pressure drastically above the linear rate that you get from the rest of the throttle pedal travel range and makes the gearbox goes to lowest possible gear allowed at the road speed you are at when you activate it.

Adjustment of Cable.  The kickdown cable has no adjustment at the transmission end, it's fixed. All the adjustment is under the hood, at the throttle spindle. To adjust, loosen the cable housing jam nuts until there's plenty of slack in the cable. Pull on the cable, then let it snap back in. Listen carefully, and you'll hear the cam that the cable is attached to in the automatic transmission click up against its stop. Try this a few times, so you'll know the sound. Now adjust slack out of the cable, keep testing by pulling and letting go of the cable, always listening for the click inside the transmission. As you take more and more slack out, there will be a point where you've tightened the cable just enough so the cam inside the transmission can no longer click up against the stop, because the tightened cable won't let the cam go back far enough. When you reach this point where you just stop hearing the cam click against its stop, the cable is adjusted properly.

Kick-Down Cable Replacement. [Symptom: I just found out the kickdown cable on my 88 240 [Note: same on 7xx/9xx] won't retract. I'm inclined to fix it my self but don't know what cause it and how difficult to fix it. [Repair Procedure:] Parts are about $100 - $75 for the kickdown cable, $25 for tranny pan gasket and filter. It's about an 1-1/2 hour job, very messy though as you must drop the tranny pan. You kind of need an assistant to help with the cable, and a long pair of narrow vise-grip pliers. Basically : [More Tips from Don Foster] Replacing the cable is straightforward.   If you have the pan already off, swapping in a new cable should take only a few minutes.   Look in where the cable attaches, and you'll see a cam-like or pulley-like gizmo around which the cable wraps. You can (carefully) turn this with a sharp tool or screwdriver (it's spring loaded.) You'll be rotating it against it's return spring, and as I recall it's a little tricky. Once rotated to the fully extended "full throttle" position, stick a screwdriver in to wedge it and you should be able to pull the cable end free of its hole.  The old cable will disengage -- it has a round thingy at the end fitting into a recess.
The tranny end of the cable housing friction-fits into the tranny housing. I'd clean and blow-dry the outside area before removing the old cable. As I recall, you can "pop" if out with a screwdriver -- and "pop" the new one in similarly. I used a touch of synthetic grease on the O-ring-like seal.
Once installed, you install the upper end and adjust it so it just slackens when the throttle's at idle. Also, you should be able to hear the tranny valve "clunk" slightly when it slams back to idle. Install the small crimp around the cable core about 1/8" upstream of the orange rubber gasket.  This crimp is sorta important -- it prevents excess cable from entering the tranny and keeps the cable in the pulley groove.

Transmission Not Shifting Out of Park

Symptoms.   [Query]  My transmission will not shift out of park when I step on the brake.  [Response: Bob] Shift lock solenoid not releasing. Possible causes, brake light switch, micro switch in shifter assembly.  Micro switch most common. Access shifter by removing cover, on passenger side near indicator is a small black switch with a metal lever. Switch about 1 in. long @1/2 in wide, mounted with a small round metal clip.  There are two black wires. You have to unbolt the shifter and lift up slightly to access switch, but don't have to disconnect anything under car. Be careful removing switch retainer as its easy to break the small plastic post the switch mounts to. To test, short the two wires together with key on and brake pedal pressed. If it now comes out of park, replace or bypass the switch.

Shift Lock Switch Replacement.  [Tips from Tom Irwin] Lately, my AT has been failing to allow a shift out of "PARK" about 90% of the time. I have to press the Shiftlock override to get going.   This car was serviced in 1996 under the recall campaign to replace a defective shiftlock microswitch inside the shifter console. The "A-hah!" went off in my head because I have been substantially underwhelmed about the abilities of the dealership where I purchased the car.
I got out the books and went looking for trouble. To get at this thing, it is advisible to remove the following parts, roughly in this order:

Automatic Shifter is Loose. [Symptom:] The shifter on my 745GLE (automatic) is really loose. When I put it in park, I heard a metallic clunking. I can move the shifter about a half inch at the top forward and back (no side to side movement) when it is in any position. [Another Symptom on an AW:] Last week I noticed I has having to over shift my '89 700's AW to get the car to go in gear. In general the shift lever was quite sloppy.
[Diagnosis:] There are bushings that fit in the ends of the shift linkage rod and when these are shot, the shifter is pretty much adrift. They have to be among the cheapest parts available from Volvo, and replacing them makes a world of difference. Be sure not to lose the clips that hold the linkage together and for heaven's sake, don't take the whole thing down - do one end at a time and save your self the grief of not being able to remember which way it went.
[Repair Tip from Don Willson:]  Saturday I put it up on the jack stands and looked at the linkage. There were 4 places where a pin (about 1/4 inch diameter) goes thru a hole (about 1/2 inch dia) and is held on by a snap ring and washer. In every case a rubber bushing that was supposed to be there was gone. So I replaced all four and it surely made a difference in the shifting, now when I move the lever to D it goes into drive.
If this fits you you need 1 #1220141, and 3 #381704. These look to be a silicone rubber rather than the old black stuff. It took about an hour. You can remove all 4 starting from the easiest to get to and working up and forward. Replace them in the opposite order. The parts are about $2.50 each so it is not a budget breaker.

Shifter Moves.  [Query]  I have a 1990 740 Sedan Turbo. When I drive the vehicle and apply the brakes the automatic transmission shift lever and gear position indicator (P, R, N D, 2, L) moves!  Any ideas on what causes this?  [Response: Bob]  The shifter is conected to the transmission by two rods. One rod actuates the shift lever on the transmission; the other rod is called a reaction rod and connects the shifter to the transmission case. If you remove the reaction rod from the case, the shifter and indicator will move back and forth. With every thing hooked up and adjusted properly, the shifter will move some when stopping, starting, shifting from R to D, etc.  It is DESIGNED to move with drive train movements. This prevents the need for occasional linkage adjustments. If it moves a lot, check engine and transmission mounts. But some movement is normal. [Editor: see above notes on shifter rod bushings.]

Auto Tranny Refuses to Reverse: Bad Mounting.  [Query:] My 87 764 Turbo has 124K miles and the AW 71 transmission has been serviced every 25-30K miles. Recently it has started to "refuse" to go into "R" gear after 10-15 miles of operation in "D". The selector seems to operate normally with all the usual detents, but the transmission is still in pseudo-"D" when the selector is in "R" as the car will creep forward. Putting the selector into "P" results in a slight lurch forward and then the transmission is properly locked in "P".  [Response 1:  Rick]  Sounds like the linkage is miss-aligned. That is, your gear lever isn't aligned to the gears positions on the transmission.   [Response 2: Michael Jue ]   It could be something more (read: internal) but I'd concur with Rick on this being the first course of inspection. Something else you should seriously consider...especially if the shifter is maladjusted as above: the rear transmission mount. I'd been having a number of small niggly shifter issues in which the shifter "felt" right but the indicator never showed in the clear windows at the base of the shifter. Then, finally the neutral safety switch failed to work.  Diagnosis: bad transmission mount. Sheared the rubber mount from the metal surrounds. Easy fix. (Jack up, support tranny, unbolt crossmember, remove old/install new mount. Replacement the opposite of removal.)  Who'da believed it? I've never had  a broken trans mount before. All symptoms disappeared.

AW-70L Transmission Life.  [Query:] Any thoughts out there on the life expectancy of an AW70 tranny. I've got a 745 with 145K and it seems strong. I flush the fluid every summer. I know some think this is not good, but it seems to work. Are the AW70's rebuildable or do you just replace them?  [Response 1:] I had a minor problem with this tranny (worn check valve in the valve  body, which caused it to shift hard between 1st and 2nd gear). When it was fixed, I also asked about the tranny in general, and I was told that these units usually require a rebuild at about 350 000 kilometers, or more than 200 000 miles. And only the clutch and brake packs need to be replaced, usually all the bearings are still OK.  [Response 2:] They can go 250 K. They can be rebuilt, that box is shared with several Toyota rear drive 4 cyl models in the early to late 80's.

AW-70 Maintenance: Bands?.  [Query:] I recently acquired a Volvo with an AW-70 in good condition from my brother-in-law. I am planning to flush the ATF and replace the filter in the near future. My friend suggested adjusting the bands while I have pan off. Is this a reasonable thing to do? Does the AW70 even have adjustable bands? The Haynes manuals are silent on the subject.  [Response: Abe Crombie] The AW55/70/71/72 and BW55 don't have bands. These gearboxes use friction discs as brakes.  Disc brakes don't require (nor is there any way for) adjustment.

Seal Leakage in AW70L Transmission.  [Query:] Oil is leaking from my AW70L transmission at the shift linkage shaft on the right side of the tranny housing. Does anybody know how it is to replace the seal(s)l ?  [Response:] That shaft goes through the tranny from one side to the other, with a seal on each side. On my '83, the seal had simply popped out of the transmission housing, and only had to be gentle pushed back in. The bad news is that -- at least in my experience -- access to the seal is restricted by the exhaust pipe. Dropping the pipe first made it much easier.  One thing I'd advise is to first clean up that area of the transmission, particularly if it's been leaking for awhile. A lot of dirt and grime will accumulate -- and you want the area as clean as possible before installing a new seal. I washed it down with parts cleaner, hit it with compressed air, and let it dry.

Stripped Trans Drain Plug.  [Query:] Did a routine fluid change. Detected a slow leak from the plug area a few days later.  Removed plug. Threads were stripped. Purchased new plug. Unable to get a tight fit since threads in pan probably also be damaged. No leakage yet, but I fear that plug may eventually loosen, I'll lose fluid and destroy the tranny. (so much for preventative maintenance.)  Replacing the fluid pan seems to be the obvious solution. I would appreciate any suggestions on a good source for a pan, or alternative solutions to the problem.   [Response: Simon Eng] No need to replace the pan. There is available a kit specially designed for this purpose. My mechanic has several sets and he let me borrowed one of the sets.  First check what size is the plug. Let say it is 12 mm by 1.5 mm. The kit for this size has a drill bit and a tap with 14 mm by 1.5 mm. You drill the drain hole with this drill bit, then thread the hole with the tap. There is an insert that has 14 mm by 1.5 mm on the outside and 12 mm by 1.5 on the inside. Screw this insert intp the hole and use the supplied expander to expand the insert and to position it on the threaded hole. Now the insert is firmly anchored. If the old drain plug is still in good shape, reuse it; otherwise get a new plug.   [Response 2:  Kane] Naturally, in upsizing the plug, you'll need to tap new threads for the hole too. Drill the hole smooth, then tap - you don't want the new threads crossing the old ones.  You may also try "chasing" the existing hole with the exact tap size and thread count as the current plug. Sometimes this is all that's necessary to clean the remnants of the old plug and whatever else is stuck in the threads.  This assuming that you do have a tap and die set. Otherwise, plucking a pan from the junkyard may be the best bet.

Transmission Line Crack Prevention.  [Tip from Tony P]  My lines actually rubbed together long enough to cause a leak. I removed the clips and installed a compression fitting to repair the leak. Then I cut some sections of rubber hose, slicing them lengthwise so that I could slip them over the transmission line. Then, using a zip tie or tie wraps as they are called, I secured the rubber hose around the transmission lines to stop chaffing.

Turbo Lockup Torque Converter Function.  [Query:] My 1989 745T with AW71 has a lock up torque converter that is locking and unlocking too much. At some speeds and loads and boost levels, it constantly locks and unlocks until I either back off or speed up.  [Response: Abe Crombie] A US market spec Volvo rear wheel drive turbo doesn't have a locking converter. If yours has a locking converter the ID plate on driver's side of gearbox will read "03-71L" or possibly "03-70L" if someone has changed it.  The lockup control in either case is a function of it being in 4th gear and governor pressure reaching approx 50 psi. A lock/unlock at threshold of locking speed can be caused by a worn bushing in tailhousing allowing the gov. pressure to fluctuate. This can be checked by attaching a trans press. gauge and reading the gov. pressure at speeds around 45-55 mph to see if the pressure is stable as speed is brought that range gradually.

ZF22 Damage in Park.  [Query] I have a 1986 740 GLE. I took the vehicle for emissions testing in March. Part of the test is to rev the car for several minutes while they check the high idle (2500 rpm). My transmission started slipping badly when I left, and lost all forward gears the  next day. I replaced it with a junkyard tranny (I know its a risk, couldn't afford a rebuild) and the car has run great for about 3,000 miles. My tags have expired, so I went back for another emissions test (it failed the first time).  Unfortunately, it failed again, but this time, it would hardly move. I made it about 1 mile, then had to be towed. I was told by a transmission shop that the ZF 4HP22 transmission cannot be revved in park without causing damage and that a bulletin went out to all emissions testing facilities. A dejanews search found several old posts saying smog tests would kill this transmission, something about after being in forward gears then put in park, some pressure is still on the clutches and will wear out clutch pack A. This seems to apply to Volvos, BMWs and Jags with the ZF 4HP22 transmissions.  The emissions testing people have called me 5 times since yesterday, they seem concerned and are having my car towed to have the transmission checked. They will not admit to any bulletin, but obviously seem concerned about liability.  My question: does anyone have any info on these transmissions? I have heard of a Volvo bulletin on this, and an EPA bulletin (may be just California EPA, not sure). Bulletin numbers or a copy of the bulletins would be great. I'd like some facts to present them with since they are listening, but so far just have a little info from old newsgroup posts, and from  a conversation with a transmission shop.
[Response 1: Mark Aarabi] What you have heard and read is absolutely true.  Yes, there is a TSB out.(Volvo TSB 2525, 9/91, for all ZF-equipped 1985-88 740 non-turbos).. and Yes, there was a memo from EPD to all emission testing facilities about this concern (at least here in Georgia).  What state are you in and do you have any idea what type of equipment they use for testing?  The software on most BAR97 equipment will automatically bypass the 2500 RPM section of the test on these particular vehicles.  [Response 2: Bruce] Most all  emissions center should be aware of this problem. Other cars have the same problem that use the ZF tranny. As the one post stated the test machines will by-pass the rpm test with a ZF tranny. The emission shop should replace your tranny. But getting them to admit fault and do it could be a problem.  For others reading this, 1985, 86 and 87 only 740's used the ZF tranny. (Editor's Note: ZF-22 cars have "P-R-N-D-3-2-1" on the shift quadrant and NO overdrive button on the shifter.) Turbo models use the AW-71. For the above model years, if the gear shift lever does NOT have an OD button you have a ZF tranny. With an OD button you have the AW-71 tranny.  One way to test the emission on a ZF tranny is to raise the back wheels off the ground, put the car in drive and rev it up to 2500 rpm for testing. In gear it will not do harm. In neutral or park and revving, the tranny pump does not pump oil.  I was told this by a transmission repair center.
[Editor's Note: Summary of Volvo TSB 2525, 9/91:]  Before beginning the "High Idle Emission Test Sequence" make sure the car is at operating temperature.  Place transmission into "park" and switch the ignition off for 30 seconds.  Restart, but DO NOT move the selector through the forward or reverse gears before or during the test and DO NOT EXCEED 2000 RPM.  The first stage of the test is at 1850 rpm for 30 seconds, the second stage is at normal idle for 30 seconds.  If you fail the test and have to do it again, then DO NOT proceed with the programmed catalyst preconditioning test sequence.  Abort the test, place the transmission into "park", precondition the catalyst at 1850 rpm for 4 minutes, then allow the engine to revert to normal idle and check the tailpipe emissions.  Under no circumstances must you exceed 2000 rpm during any part of the test.

ZF22 Fails; Swap for AW?  [Query:] The ZF4HP22 tranny in my '86 740 just started spewing fluid from inside the bellhousing (1 pint/mile). Given the reputation this tranny has, I'm undecided as to whether I should rebuild it or replace it with an AW71. Has anyone done this swap?  [Response:] Do the swap. Any AW70 or 71 will work from 82-on. The basic gearbox is the same, but some are better or stronger than others. If you're going to buy one from a junkyard, get one from the latest years possible. (89-93 non turbo, since they have a lock-up converter.) If you use an earlier gearbox, you will need to plug the speedo drive hole in the output shaft housing.  I don't remember if the flex plate is the same or not, you may need that. The driveshaft is different. If you order it from the boneyard, tell them you're doing the conversion.  Remember that the car didn't know what transmission it was going to get, so the interchange is ''bolt in.''  I think if you get the necessary parts (with relatively low mileage) for under $1000.00 you did all  right.
[Response 2: Dick Riess]   Actually quite easy to do.  Best bet is contact someone like Strandbergs in WI 800 448 5121 and they literally send you a good used unit plus all parts. I did an 86 740 couple of years ago and works great. BTW, be sure to put a new rear main seal in at the same time.   Here are the parts you will need: transmission, cross member, motor mount rear, drive shaft front half, gear selector unit, relay for overdrive on AW unit, some wiring. Get good wiring diagrams to help you out.

960 With AW-30/40 Has Busy Shift: Electrical Glitches.  [Query:]  I have a '92 960. The car has 95,000 miles. I have noticed that the car seems to shift frequently. The best way to describe it is that it is "busy". It is more pronounced in traffic when there is a lot of stop and go. It seems as if it slipping in and out of gear. I have had it at the dealer twice and they agree it is "busy", but can not give me a reason. Any ideas?
[Response: Abe Crombie]  The mileage on that car and the symptoms make it a candidate for a failing throttle position sensor.  This can be monitored by their Volvo scan tool on a drive while it is overshifting. The transmission computer uses this signal read directly from TPS by Fuel computer which passes it on to trans computer. You could unplug the TPS (this will set code/turn on check eng light) and drive the car and see if it shifts less and holds gears better. There will be a default signal from ECM to TCM when the signal is missing.   [Query: Similar Problem]  '93 960 ran smooth and quiet before I brought it in for tranny service, and it still does. But since the servicing, the tranny searches around a bit at times. The tach indicator will jump forward and back, then forward again, and ther car lurches.  [Response: John O] Changing ATF will not make the trans act up unless someone put in the wrong fluid (like Ford Type F, not likely).  What I've seen a couple of times with early 960s (especially '92s) was a corrosion (oxidation) problem affecting the large electrical harness connectors on the left, upper area of the transmission, seen from under the car and near the dipstick area. Remove the plugs from the bracket, unplug them and spray inside with electrical contact cleaner, let it dry then re-install with silicone dielectric grease smeared insided the wire connectors. I've seen this help a couple of our customers who previously experienced unusual trans problems and worth trying before condeming the trans itself. [Tip from Tom Irwin]  Those connectors can be hard to separate: use caution, they crack easily.

On-Board Diagnostic Codes for AW-30-40 Series Automatic Transmissions.  [Tips from Tom Irwin]
These electronically-controlled transmissions also contain a diagnostic code series that you can access easily from the engine DLC module (the same one as used for the ignition and fuel injection codes.)  Note that this procedure for code retrieval works only for OBD-I (pre-1996) 960 cars.
1. Open DLC, (Diagnostic Link Connector) insert Test lead into hole #1.
2. KEY IN position 2, engine NOT running.
3. Push and hold DLC button for >1second, but, <3 seconds and release.  (have your pen and paper ready)
4. Codes are three digits, separated by pauses, so a "314" would look like: " -*-*-*- (pause) -*- (pause) -*-*-*-*-"
5. After a longer pause, additional codes will be given, when you see the first code have returned to the starting point.
6. Code "1-1-1" means all Clear, no codes set.
7. To erase codes, al codes must have been read off at least once, then press and hold the button for >5sec. release, wait for LED to light, then hold button for >5 sec again. And you are cleared.
There is also a self-test mode you can enter which is a two man job. One enters the code through the DLC and the other guy is under the car feeling for each solenoid and other device to activate in sequence. Then, you can run through all the gear positions and modes and the DLC will respond with a code that shows the input was good or not. Good for isolating bad components.

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