Transmission:                                                                                                     Version 3.0
 
In-Line Filters 

Fluid Flush  

ZF22 Transmission Fluid Drain 

OD Switch Repair 

OD Relay  

Auto Trans Overdrive Problems: Solenoid 

Transmission Output Shaft Bushing 

A/T Won't Upshift 

Kick-Down Cable Adjustment 

Kick-Down Cable Replacement 

 Automatic Shifter is Loose  

AW-70L Transmission Life 

ZF22 Fails; Swap for AW? 

Manual Overdrive Fails to Engage: Basic Diagnostics 
  
Manual Transmission Overdrive Solenoid 

Manual Overdrive Clutch Slipping 
  
Seal Leakage in AW70L Transmission 

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

 

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)

I actually performed a variant to the above theme: 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 bucket. 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). 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.


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. [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 source...it appears to be a standard Hella relay.

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.


Transmission Output Shaft 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 alone...it 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. 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.

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.

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?


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. 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 :
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. [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.
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.

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.

Manual Overdrive Fails to Engage: Basic Diagnostics.  [Query:] 740T car has a 4 speed manual transmission plus overdrive. The overdrive is the push-button type on the end of the shifter.   When the car is hot it will not shift into overdrive. I just changed the transmission fluid and cleaned the strainer but I still have the problem. Here are some basic conditions: [Response 1: Filters & Fluid]  A frequent cause (not yours) is clogged filters inside the OD unit. Can be cleaned (with white spirit) without removing gearbox or OD. Also synthetic  ATF (or redline MTL) will help. The reason it does not engage when the car is warm is that the gearbox oil is also hot - and thus thinner, so  it's pressure drops. Synthetic oils do not change their properties (so much) when heated, this is one of their advantages.
[Response 2: O/D Relay] Bosch relays have a serious habit of becoming intermittent and/or temperature sensitive.   98% of the time, it's solder connections on the printed circuit boards inside the relay assembly. You can pop the plastic cover off and examine the backside of the PCB with a magnifying glass. More often than not, you'll find microscopic cracks in the solder around some of the connections. I have been quite lucky re-soldering and reviving virtually ALL the relays in my family's Volvos.
[Response 3: Electrical Wiring to Solenoid] Check the wiring to (and connections at) the overdrive solenoid.
[Response 4: Basic O/D Electrical Diagnostics] There are a couple of good diagnostics and inspections that you or a willing mechanic can easily perform. Given that you changed the oil, at least you know where the OD is, so maybe you and/or a friend can dive right in.. Try these: [Response 4:Rebuild]   Finally, it may be time for an OD rebuild.  The OD uses the pressure of the oil in the tranny to engage.  When the tranny is cold, the pressure is greater, so the OD works.  When it gets hot, the pressure is less so the OD does not work.  You really have two choices, find a reputable shop to rebuild your OD, or find a used OD.  If you are playing around with extra boost in your car, you will want to have the OD rebuilt to handle the extra power.

Manual Transmission Overdrive Solenoid. I checked at a few volvo dealers for the cost of a volvo OD solenoid and the price was between $195 and $215. Then I ran into the Gear Vendors (World's largest supplier of Overdrive Auxiliary Transmissions) at the Los Angeles Roadster Show. Their price for new OD solenoids for the Volvo is $100. I spoke to Homer Eubanks at 800/999-9555 (customer service rep) and he was very, very helpful diagnosing a problem I had with my OD when it would go off/on/off/on/off and finally off. He told me that the OD needs servicing and when that is done that I should have the screen cleaned and air blown through the small oil holes that go to the solenoid.

Manual Overdrive Clutch Slipping.  [Query:]  I  posted a message about this problem a couple of weeks ago, or so, and one respondent suggested engine mounts, but after inspecting them, I doubt that they are the cause of this problem. The car is an '89 740 Turbo with M-46 plus P overdrive. When the car is good and hot, the overdrive clutch seems to slip. Starting out in 1st gear, I get a lurch, during which the engine revs slightly, then settles to normal. Sometimes, in any forward gear, in overrun, the engine drops back to idle, as if the overdrive was neither engaged nor disengaged and was freewheeling. In reverse gear, I get a loud gear whine, and the car  proceeds at a clearly much lower ratio for 20 - 30 yards, then lurches into its normal ratio.  At these times, the overdrive will not engage at all, but it doesn't feel like the direct drive has disengaged, because there is no freewheeling. In cool weather, or when the car is not stinking hot, the overdrive works perfectly. The electrics for the overdrive all check out. The car is new to me, has 85,000 miles, and seems to have been very well cared for and driven lightly. Should I just assume that it has the wrong kind of oil (i.e. Dexron), or should I consider other things? Is Redline really the magic bullet for these units, or is Volvo's stuff better? The Volvo manual seems to suggest that Volvo's oil is only good where ambient temperatures remain above 10 degrees Fahrenheit, not a safe assumption here in the Boston area. If incorrect oil is the likely culprit, what should I do to clean out the old stuff?  [Response:] Try draining the trans and O/D. Clean both screens in the O/D. The one under the rectangular plate as well as the one on top of the big plug once you get the cover off. Type F will work fine for the trans./O/D. O/D's can slip both unengaged as well as engaged. They usually slip when engaged though.  This is a first step and it's a lot easier to do them pulling a gearbox.

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.

A/T Fluid Needs Changing; 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.