FAQs about Transmissions.

  • Should I flush the cooler after rebuilding my auto transmission?
  • Information about the temperature sensor in my transmission.
  • Diesel transmission does not fit gas car without modifications.
  • Are Volvo transmissions serviceable?
  • Pulling my transmission.
  • I've got a leaking transmission, how can I fix it?
  • Does a manual transmission have an inhibitor switch for neutral.
  • Will an automatic transmission roll while in Park?
  • Transmission failure prevention.
  • Use a transmission cooler for towing.
  • How can I fully drain the automatic transmission fluid.
  • How can I tell the difference between a ZF unit and the AW unit?
  • How do you replace the rear main seal?

  • Should I flush the cooler after rebuilding my auto transmission?

    From: kaleb@thyme.jpl.nasa.gov (Kaleb Keithley)
    Subject: Re: Auto tranny - cooling system cleaning
    To: volvo-net@me.rochester.edu
    Date: Thu, 10 Oct 91 7:53:17 PDT

    > finally got the tranny in the car. I need to flush the
    > cooling system (basically the lines and the in-radiator
    > cooling tank for the tranny. anyone have any good ideas?
    > if I take off the line that RETURN FROM the radiator,
    > and overfill the tranny by a couple of quarts and let it
    > idle for a few seconds, do you think fluid will come out
    > the hole in the tranny where the return line would go
    > (as well as out of the return line which I would want)...

    I'd advise against this. It'd no doubt work, but you run three risks.

    First, and most important, if you run for a few seconds too long, and run the trans dry, you'll fry all the thrust washers and bearings. Undoing all the work you've done so far. There is at least one roller bearing type thrust washer in the torque converter, too, which of course, you can't replace without replacing the torque converter.

    Second, even at low RPM, the trans pump generates 80-100 PSI. (Higher RPM doesn't matter because there's a pressure regulator.) I don't know about you, but I don't like the idea of 100 PSI fluid being pumped out all over my garage floor. Just be carefull.

    Third, overfilling the trans for any reason is a bad idea. You can't really add too much more anyway, most of the trans case is full of the clutches and planetary gears, not at all like a manual trans. Overfilling only results in foaming, or aerating the fluid, which is just a bad idea.

    I have a few thoughts. One, in all the auto trans that I've rebuilt, and I've done quite a few in my time, I've never bothered to flush the cooler. My rationale is that if you look at a trans fluid flow diagram you'll see that the flow is: filter, pump, cooler, valve body, etc. Unless the old filter was compromised, there's little chance that any crud got into the cooler. Two, if it's a rebuilt or remanufactured unit, the initial break-in is going to generate a lot more crud than could possibly be in the cooler. It doesn't matter how immaculate the trans was when it went together, the nature of the friction material used in the clutches always loose some material initially. Third, most trans shops have a tool, which you can duplicate easily; a drill motor, a low pressure pump that attaches to the drill motor, some rubber hose, and a tank of automotive type cleaning solvent. If you still want to flush the cooler, use this setup. It's easier, cleaner, and less prone to fry your trans. Fourth, with a rebuilt/remanufactured unit, after a month of break-in, drop the pan, clean the crud out of the pan and change the filter. Change the filter and fluid once a year thereafter. Always change engine oil and trans fluid after the unlikely event that the car overheats.

    Kaleb Keithley kaleb@thyme.jpl.nasa.gov
    Not authorized, in any way, shape, or form, to speak for anyone.

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    Information about the temperature sensor in my transmission.

    Date: Wed, 18 Dec 91 17:09:34 EST
    From: nick@meaddata.com (Nick Gough)
    To: volvo-net@me.rochester.edu
    Subject: Re: O/D Off lights Autos

    Dave & netters...

    I noticed this feature on our 760 with the manual 4-speed w/elec. OD recently. The OD wouldn't kick in until the tranny reached a certain temp (so many miles). Everytime this occurs (it's gotta be downright COLD... & was a couple of weeks ago, but then warmed up & then cam the flu epidemic, but that's another story) I am surprised until I remember that little feature. It doesn't mention it in the owners manual, as the owners manual only refers to the V6/auto setup for our 1984 760, although everything else (warranty card, & 1984 shop manuals...even those from Haynes) mentions the fact that it is a 1984 car. Once, even a dealer didn't know about this car being a 1984 & swore that it was never made then, but was a 1985 model. Once I gave them the serial # & other info, they were amazed! I was right. I digress...

    Peace & good health to everyone.

    Nick Gough ------------------------------------------------------------------------------- | Nick Gough (nick@meaddata.com)| The views/opinions expressed here are not |
    | Mead Data Central | necessarily those of my employer. |
    | P.O. Box 933 | |
    | Dayton, Ohio 45401 | |

    ----- Begin Included Message -----

    Date: Wed, 18 Dec 91 15:11:15 EST
    From: damouth@maple.tc.cornell.edu (Dave Damouth)
    Message-Id: <9112182011.AA04436@maple.tc.cornell.edu>
    To: tim@me.rochester.edu, volvo-net@me.rochester.edu
    Subject: Re: O/D Off lights, etc.

    Tim says - -

    >No tempertature sensor on my 1979 wiring diagrams, nor mentioned in the Haynes manual (260 series).

    My automatic transmission seems to have a built-in temperature sensor (probably unintentional?) In cold weather, the top gear won't engage below about 47 mph until after a couple of miles of warmup. I've heard others mention this kind of behaviour too.


    ----- End Included Message -----

    Date: Wed, 18 Dec 91 15:11:15 EST
    From: damouth@maple.tc.cornell.edu (Dave Damouth)
    To: tim@me.rochester.edu, volvo-net@me.rochester.edu
    Subject: Re: O/D Off lights, etc.

    Tim says - -

    >No tempertature sensor on my 1979 wiring diagrams, nor mentioned in the Haynes manual (260 series).

    My automatic transmission seems to have a built-in temperature sensor (probably unintentional?) In cold weather, the top gear won't engage below about 47 mph until after a couple of miles of warmup. I've heard others mention this kind of behaviour too.


    From: matula@cblpo.att.com
    Date: Wed, 18 Dec 91 13:17 EST
    To: volvo-net@me.rochester.edu
    Subject: O/D Transmission light

    I owned a 83 automatic, and had the exact same problem with symptoms.

    Problem was that the wire was frayed and broke on the solenoid connection at the transmission (exposed to the elements, it will corrode...)

    Slide underneath, and see if the the wire to the transmission is sound at the transmission. Hope you find it frayed!

    Val Matula

    Date: Wed, 18 Dec 91 10:16 MST
    From: tech@cs.athabascau.ca (Richard Loken)
    To: Jeff.Kaplan@ub.cc.umich.edu
    Cc: volvo-net@me.rochester.edu
    Subject: OD light auto

    Sam Pottle is basically correct but he has a manual and it works in reverse to the automatic (in a manual the light is on in overdrive and in an auto it is on when od is locked out).

    I would be less inclined to suspect the wiring in the automatic since the shifter gets less exercise but look at that and check that the fuse is making good contact (it is listed in the owners manual) and then there is the relay behind the dash. The relay would not be my first suspect since the symptoms point to a poor contact in a connector or fuse or a broken wire that makes intermittant contact. There is probably a solonoid in the transmission but I don't suspect it because if it failed the light and the switch would most likely continue to work normally but nothing useful would happen.

    Some relays are under the instrument cluster and some are behind the centre console and those are a big pain in the neck to get out. DArned if I know were the overdrive relay is and I have no idea how to open up the shifter linkage if the problem seems to be in there.

    Get the Haynes 240 manual from your nearest import parts emporium - it has a nice assortment of wiring diagrams which will make this job approachable. A voltmeter would be a big help here and a $25.00 Radio Shack analogue multimeter is nothing on labour costs.

    As for me, I have finished rebuilding my clutch and driveshaft and the car seems quite pleased with itself.

    Richard Loken VE6BSV : "In England, Justice is
    Athabasca University, Athabasca, Alberta Canada : open to all, like the
    tech@cs.AthabascaU.CA : Ritz Hotel."- Lord
    {atha|aunro}!cs.athabascau.ca!tech : Justice Sir James Mathew

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    Diesel transmission does not fit gas car without modifications.

    From: matula@cblpo.att.com
    Date: Wed, 29 Jan 92 07:57 EST
    To: <volvo-net@me.rochester.edu>
    Subject: Re: Transmission swapping

    A Diesel tranny does not go into a gas car without some modification.

    Reason: Bell housing is different. Starter on diesel (a.k.a VW/Audi "6000") is on passenger side. Starter on B23 is on driver side.

    Now, if you can find a gas bell housing, then they match right up.

    I have taken an automatic from a 1981 diesel (BW55), swapped the bell housing from the 1979 gasoline unit, and placed the result into the 1979 car. The torque converter between the two was different, so I had to swap the converter also.

    For the manual transmission, you might want to check if the clutch plate and pressure plate are the same. I seem to remember reading that the diameters are different by 1/2 inch. I'll look in my manual tonight for details.


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    Are Volvo transmissions serviceable?

    Subject: Re: Transmission/Drivetrain Noises
    To: lmk2q@honi1.acc.virginia.edu
    Date: Tue, 14 Apr 92 12:13:44 PDT
    Cc: swedishbricks@me.rochester.edu

    > >> What exactly do you mean when you say that Volvo transmissions
    > >> aren't "serviceable"?
    > What I should have said is that Volvo automatic transmissions, which I believe
    > are a Borg-Warner, cannot be rebuilt according to Volvo and various
    > publications, including Haynes. Since these transmissions cost in the
    > neighborhood of $3000 for replacement, I want to be certain that my problem
    > of shifting into reverse is not causing any damage to the gears in the
    > transmission. Obviously, typical maintenace such as changing the fluid and
    > the filter screen must be performed regularly.

    To me, non-serviceable usually means no bands to adjust.

    There isn't a transmission alive that can't and shouldn't have the fluid and filter changed once a year. Your mechanic, or barring that, a trans shop or even your Volvo dealer should be able to service your trans for US$100 or less. An overhaul/rebuild by a reputable transmission shop around here for Euro automatics seems to be US$700-1200. Considerably less than $3000!

    Most modern automatics (Honda and Saturn excluded) use a planetary gear train; you can't "hurt" the gears in the same way you can with a standard transmission. That doesn't mean you can't fry the clutches or disintegrate bearings and thrust washers, or flood the trans with metal shavings.

    I don't have any experience with the late model over-drive automatics. Over-drives were still too new for me to have seen any of them while I was involved in the auto trans repair industry. Never the less, my book learning about the over-drive units leads me to believe that my three speed experience is just as applicable.

    With that said, on the three-speeds, third gear and reverse were both handled by the "direct" clutch. Lack of, or noise from, or slipping in, reverse is usually accompanied by lack of, or noise from, or slipping in, third as well. In a marginal unit, it may not be as apparent due to the fact that the car is already rolling when the unit shifts into third, in contrast to a standing or rolling stop when the unit is shifted into reverse. There's a lot more break-away friction involved in getting a car moving from a standing stop; and explains why many manufacturers bypass the pressure regulator and supply full, unregulated, pressure to the direct clutch for reverse gear.

    So, I don't recall what the original symptoms were, but I would highly recommend that you have the trans inspected by a qualified transmission specialist. Soon!

    Kaleb Keithley kaleb@thyme.jpl.nasa.gov
    Not authorized, in any way, shape, or form, to speak for anyone.

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    Pulling my transmission.

    Date: 26 Jul 1992 14:09:22 -0400 (EDT)
    From: "John W. Retallack" <JWRPPH@ritvax.isc.rit.edu>
    Subject: Re: Pulling the transmission
    To: jhenders@jonh.wimsey.bc.ca
    Cc: swedishbricks@me.rochester.edu

    I agree with most of what's been said RE: pulling the transmission. Here are some additional thoughts:

    1- Safety! No matter how you get the front end up make sure it won't come down on you. I've known several professional mechanics... It's not a nice way to go. I use axle stands and place wood or concrete blocks under the car in some out of the way but secure spot to prevent the car from coming down all the way. Be especially careful if you are not working on a concrete surface. This is most important if you have the wheels off! (you won't if you are only doing a clutch).

    1a- You'll need something to support the back of the engine while the transmission is out. I use a bottle jack (hydraulic) and a 6" square block of wood under the oilpan. The wood spreads out the load, cut a hole in it to clear the drain plug.

    1b- Disconnect the shift lever and remove the boot from inside the car. Also disconnect the overdrive and back up light wiring.

    2- I don't remember seeing allen bolts (transmission to bellhousing) on anything later than an early 140. Allen sockets are available (Sears) or you can make one as previously described. 3/8" will work, actually, I think they're metric. Also fits B21 head bolts. A universal joint for your socket set is useful. Also a new (to me) gadget called a wobble drive is useful here (simply, a loose fitting extension bar). Plenty of room on 140's & 240's but a very tight fit between the transmission and the floor tunnel on 544's and 1800's.

    3- On earlier cars the transmission can be separated from the bellhousing leaving the bellhousing attached to the engine. Starting with the B21 and M45 & M46 transmissions, the bellhousing is attached to the transmission with bolts from inside the bellhousing.

    4- I don't remember any unusual problems when I replaced the clutch on my B21 ('76) but... The transmission is heavy. I used a floor jack with wheels. A bit touchy but it worked. Probably two strong guys could handle it. The bolts on top of the bellhousing are accessible from above. All Volvo's use metric bolts after 1975. I think these are 17mm. Disconnect the battery before you remove the starter! I suggest wearing gloves when man-handling a transmission.

    5- Rear main seal. If it shows signs of leaking, replace it. Otherwise I'd leave it alone. Note: there is always some oil inside the bellhousing. Sometime in the early '70s the felt seal was replaced with neoprene. When replacing this type they should be installed to "run" in a slightly different spot. IE: not in the groove they have worn in the crank. Printed instructions came with the seal I got from Volvo. The Haynes manual covers this too. Put some grease on the "lips" of the seal before refitting, soak the felt seal in oil (early models).

    5a Examine the old clutch. According to the Haynes manual; the clutch facings should look like smoothly finished wood, light in color. The grain should be visible. If oil leakage has been present the facings will look like varnished wood, darker and the grain may not be visible. Some oil is always present. Haynes says that if the finish is smooth and the grain is visible oil leakage is not a problem.

    6- Pilot bearing (input shaft): Always replace it when doing a clutch job. If it seizes it will keep the transmission input shaft turning even when the clutch is disengaged. You'll think your synchro's are bad.

    7- Flywheel surface: Check for deep grooves. It can be resurfaced at a machine shop. If you want perfect shifting, the surface must be good. If you just want to replace the clutch... I've seen some fairly grooved flywheel's that shifted OK.

    8- Centering the clutch. Can be done as earlier described. Also you can buy a centering tool (plastic) from a good auto parts store. Sometime about 1980 the number of splines on the trans inputshaft were increased so a different tool will be required for later models. I put a little grease on the splines of the clutch plate.

    9- Shift fork. Check for excessive wear where it runs on the throwout bearing. A little grease in this area too.

    10- When reinstalling the transmission it helps if it is in gear. When all is lined up you may have to turn the ooutput shaft to engage the clutch splines.

    11- I torque clutch cover (pressure plate in US jargon) to 25 ftlb (Haynes does not give specs). The flywheel gets 50 ftlbs. I also use loctite. A big screwdriver engaged in the starter drive ring will prevent the engine from turning.

    12- Parts suggested for a complete job: Clutch, clutch cover, release bearing, pilot bearing & possibly rear seal, rear seal housing gasket & possible machining of flywheel surface. I've done it with a lot less and not been unhappy.

    It's not as difficult as all this seems but you'll know you've done some work! Sorry for the long post:


    From: matula@cblpo.att.com
    Date: Mon, 27 Jul 92 09:06 EDT
    To: swedishbricks@me.rochester.edu (Volvo-Net)
    Subject: Transmission removal(s)

    My two cents, after others:

    >Yes you can pull the transmission without pulling the engine but the differance
    >in work is marginal.

    I've done it both ways. To just do the transmission/rear seals, its easier to just pull the xmission. IF you also think you want to redo the coolant pipe, look over the engine, perhaps replace a oil pan gasket, etc., then prepare the hoist and pull the engine. However, if you have the following, you can do just the xmission without a lot of hassle:

    Jackstands for safety.
    2 1/2 ton floor jack, or something simiar with a large (~4") cup at the end of the arm.
    19mm 3/8 or 1/2 inch drive sockt for those three bolts at the top of the engine.
    1/2 inch universal
    3/8 to 1/2 adapter if you're 19mm is a 3/8
    2 foot long 1/2 inch extention bar
    1 foot or longer 1/2 inch drive breaker bar

    First, remove driveshaft connections. Note that they are 9/16" bolts (yes, on a metric car..)

    The idea is to get the jack under the transmission, place a block of wood between the engine and the firewall just under the camshaft, remove the rear xmission supports, and then lower the engine/xmission until the engine is supported against the firewall by the wood. If the camshaft on the engine touchs the firewall, get a bigger block. Additional safety can be had by putting a separate stand under the engine.

    With all this done, loosen the three top bolts, then the others, and then you and another person slide the transmission off of the engine.

    >I have done it from under and I had a pit to work in, it was as comfortable
    >as this job can get.

    If you have a concrete floor garage, you can do it.

    >If you pull the transmission (on a 240) you have to do some double jointed
    >contortions to get the top three bell housing bolts and you need to get a
    >friend to help you pull out the gearbox which - auto or manual- is both large
    >and heavy.
    >Next time I pull the motor.

    Either way is not an afternoon job. However, if you don't have a hoist, and you decide to rent one, then you'll be under the time=gun to get it done before the hoist is due back. If you don't OWN/have unlimited time for a hoist, I'd recommend that for your first time out on this job, don't pull the engine. It always takes me longer than I think the first 3-4 times I do a job.

    (After that, it takes me a little less time, but I start to more properly estimate the job ;^)

    Tip: For a pilot guide, select the deep socket from your craftsman set that matches the outside diameter of the pilot bearing. Put a long 3/8 extension into the socket BACKWARDS, so the ext. is coming out past the 12 teeth. 9/16" is a size to select first. Now, just hold it against the bearing in the depression, and set up your clutch and cover.

    Val Matula

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    I've got a leaking transmission, how can I fix it?

    Date: 05 Oct 1992 23:10:06 -0400 (EDT)
    From: V087MXGB@ubvmsb.cc.buffalo.edu
    Subject: Re: leaking tranny ZF4hp22 tranny
    To: swedishbricks@me.rochester.edu

    ok, ok, I am still trying to coordinate the collection of repair tips (etc) , but here is my first (or second ? , dont remember) tip....

    regarding the '82 740GLE tranny :

    I just did my '86 740GLE....piece of cake! I'm kind of a fanatic about it so this is what *I* did. Mind you , I have the ZF4hp22 tranny.

    I drove the car up on my most level fascimile of a car ramp (the curb) and climbed under. I was in the street (I have a stone drive so its better this way) so I placed a drip cloth under the car.

    I took some liquid wrench with me and (I *always* wear goggles under my cars) sprayed all the screws, including the socket-head-cap-screw drain plug and the fill tube fitting.

    Then I went in the house for coffee and beakfast.

    I returned and cracked the plug bolt, irst, then the tube fitting, then each pan bolt (not loosened, just cracked to make sure there would be no future trouble).

    Then I removed the plug and drained the pan (only drained a little under 3 quarts even though I had the car rather level).

    I removed the fitting line next, since its large diameter provides too much resistance torque to do with the pan loose and flopping around. then the pan bolts.

    *I* soaked the pan in solvent and wire wheeled the bolts and retainer clips.

    removing the filter required two long Torx screws be removed (size 10 I think, but not sure).

    Caution (make sure the fluid is not hot!!!!!!!) another 1/2 quart or so will *pour* out now (if you situaute yourself and your tools as strategically as possible you could maximize your coverage :-)

    There is a small O-ring (about 2.5 " diam about .125" thick) around the filter port, mine stuck to the tranny a little, make sure it comes off.

    Two tricky parts here:

    On this tranny, the pan gasket is not a typical flat design, it wraps around the pan lip. Place it in the sun well before installing, to make it soft and flexible after being folded in the box. And, Just start all the pan bolts and check for proper gasket fit all the way around (it tends to curl up).

    Also, the retaining clips tend to bend out and off the holding edge if you over tighten them. You may want to close the a little with pliers so they don't spread open.

    If you are worried about the fill tube, place some liquid wrench (or other) on the fitting threads. Then try to crack that loose before doing any other part of the job. If the plug is stuck or rusted, don't worry just lower the pan slowly and let the fluid run out one end.

    Good luck, its not a bad job at all!

    Shawn E. Thompson | Project Engineer/Mgr (716)891-3375
    v087mxgb@ubvms.cc.buffalo.edu | Leica, Incorporated
    University @ Buffalo | PO Box 123
    Graduate School of Mechanical Engineering | Buffalo, NY 14240-0123
    "Nothin ever grows in this rotten old hole, and everthing is stunted and lost..
    and nothin really rocks n nothin really rolls and nothin's ever worth the cost"
    --- Meatloaf

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    Does a manual transmission have an inhibitor switch for neutral?

    From: nessa@mentor.cc.purdue.edu (Vanessa M. Cook)
    Subject: Re: Safety Switch
    To: dmunroe@hpvclmun.vcd.hp.com (Dave Munroe)
    Date: Wed, 10 Feb 93 20:41:29 EST
    Cc: swedishbricks@me.rochester.edu (Volvo-Net)

    Dave Munroe writes...

    { > Now the @#$! service manager called and said the problem is a bad
    { > neutral safety switch.
    { > Does $145 sound right?
    { It sounds like you've got a manual transmission, right? I *used to* have
    { problems with the "start inhibitor switch" on my automatic, which exhibited
    { the same problems (i.e. turn ignition on and just get lights and no cranking).
    { $145 sounds outrageous though.

    I don't think that manuals have inhibitor switches for neutral... only reverse. It sounds like someone is trying to rip you off. If you can you should try and let the thing hang while you call Volvo of North America (or whatever) and get them to straighten the whole thing out. I would let them be responsible for the behaviour of their dealers!

    { On the auto tranny, there's a switch which follows the shift lever that is
    { designed to prevent starting the car in other than Park or Neutral. This
    { switch is connected to a plastic arm that follows the switch lever. Sometimes
    { this plastic arm becomes disengaged from the shift lever, and even though you
    { really are in Park or Neutral, the switch is sitting loosely off from where
    { it should be.

    Where is the adjustments for the gating on the auto tranny?

    Mine will shift into first without actually being moved properly into the first position. I.E. you press the button down and move the lever past the stop. Every thing else works fairly well but I would like to get the gating or stops or what ever you call it aligned correctly.

    Is it in the box with the shift lever and neutral inhibitor switch or in the transmission?


    Tedium and drudgery are good for the soul. :- Boober Fraggle

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    Will an automatic transmission roll while in Park?

    Date: 11 Mar 93 00:05:32 EST
    From: Shel Hall <76701.103@compuserve.com>
    To: "Volvo.net" <swedishbricks@me.rochester.edu>
    Subject: Rolling in Drive


    We're down one '79 245, as u6946@craywr.cray.com (David Dannenberg) relates:

    >>> Basically, my wife left the car in "Drive" after snugging up to the garage door ... turned off the key. Neither of us uses the hand brake when parking in our garage ... [it] slowly rolled out of the garage, down the slanting driveway, across the street ... rear-ended my neighbor's Ford 150 pickup truck. totalled. <<<


    >>> I didn't think a car would roll easily if left in Park, so I tried it on my 262C in the garage, with the engine off. Sure enough, gravity started my car down the driveway in "Drive". Is this normal for Volvos?<<<

    Yep, and for everything else with an automatic, too. The same "fuzzy" engine/transmission connection that lets you sit at a red light with the car in "D" and the engine running, means the engine isn't holding the car when the engine is stopped and the _car_ wants to go.

    It's normal for automatic-transmission cars to roll down hills in "Drive" or "Reverse." It's also normal for wives to park 'em that way.

    In both cases, the difference between "normal" and "desirable" should be noted.


    P.S. The lady next door has lost two Buicks this way.

    P.P.S. We had a rather large Interstate pileup here a year or so ago as a result of this sort of brain-fade. A woman in an old GM car (Chevy, I think) had a driveshaft failure on I-75. She pulled over to the shoulder, put the car in "Park," climbed out, and locked the door. The car then rolled down the hill, across four lanes of 60 MPH traffic, and whacked the center divider. I narrowly missed it myself. Putting the car in "Park" stopped the transmission, but the broken driveshaft meant the transmission was no longer connected to the wheels ...

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    Transmission failure prevention.

    Date: Tue, 6 Apr 1993 14:47:46 PDT
    From: Raphael_F._Bov.wbst311@xerox.com
    Subject: Re: Transmission Failure Prevention!!
    To: swedishbricks@me.rochester.edu

    As another owner of an aging (aren't we all) 244 automatic, I thought I'd throw out my 2 cents worth.

    I was very naive about the ubiquitous slushbox until we got an RV and planned to haul about 16,000 lbs gross combined weight with it. I have learned that "heat is the automatic tranny's enemy" and"tranny fluid only lasts so long." Sort of like milk spoilage rates: as the temperature rises, the life falls fast! Thus my use of synthetic fluid in the RV (or as much of the 18 qts. That I could change at a time) for added heat resistance and addition of a tranny temp gauge, as well as a pair of aftermarket oil coolers, downstream of the radiator mounted one.

    That said (yes, the RV's fine, despite seeing 250F when 190F is normal) let me regress to Volvos. Our '81 244 has had "funny thngs going on" in the tranny since about 90K miles. Funny, like it won't move on cold mornings until shifted and revved mildly. Sounds like sticking valves in the valve body to me. So I started faithfully changing the oil every 30K miles. Since we got the car at 73K, 90K was the first. I'm planning to change it again soon when it hits 210K. Still sticks occasionally, but it still works, too.

    Moral: I'd replace the seal and make sure the tranny fluid gets changed regularly.

    The mechanic can guarantee the new tranny will work, but he can't guarantee the old one won't. Unless you suspect that this is the first change in 120K miles, there's probably lots of life left in it yet. Volvos are incredibly tough in some respects. I've kept a head gasket leak in check in the 244 since 165K (or longer?) simply by running 20W50 oil all year round. Yes, I'm probably killing something in the winter, but it still runs ..

    Good Luck


    PS There's an interesting article in BMW CCA Roundel on the new killer Bridgestone snows. Seems they have put bubbles in the tread to allow the water that covers the ice somewhere to go, resulting in excellent ice traction!! More after I read the article.

    Date: 06 Apr 1993 18:49:53 -0400 (EDT)
    From: V093P9MD@ubvmsb.cc.buffalo.edu
    Subject: Re: auto transmission
    To: swedishbricks@me.rochester.edu


    A quick remainder to all netter with auto trannies: they require an oil change every 22,000 miles!! Dont' forget. The other day I went to check the books and realised I might be over. The ZF22PH4 has 110,000 miles on it, and it would be nice if it lasted a bit longer. The oil was a bit brownish, so I drained the oil. Since you can only drain about 2 quarts, and it holds 7, I'll change it once a week for the next month (Dexron II costs only $1.10... I could change it 1100 times for the cost of one major repair!!!). This transmission is nice since it has not filter, or seal that needs replacing often.(

    I would advise against shifting the transmission manually, especially down shifting. You are bound to put more strain on it that if you used the brakes. For that matter, brakes are a lot cheaper to replace also. I always try to avoid racing away from where I park, to let everything warm up (crusial for the turbo's life, but it should keep the trans. happier langer too). I can't claim to baby the car once it's warmed up. I regularly run it close to red line when passing to merging with traffic. It's the diesel, so red line is at 5000 RPM's. One funny thing is that it is MUCH smoother to 5000 RPM than the B23, but I digress as usual...

    Good luck,


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    Use a transmission cooler for towing.

    Date: Thu, 8 Apr 93 09:52:17 EDT
    From: 08-Apr-1993 0941 <corey@cthq.enet.dec.com>
    To: swedishbricks@me.rochester.edu
    Cc: corey@cthq.enet.dec.com

    I do a lot of towing with my vehicles so I have some experience with auto-trans coolers and their benefits. My advice is this: go to the nearest RV place and buy a BIG aux. trans cooler and install it if you want your tranny to last a long time. If you don't want to spend the bucks for the cooler then at least change the fluid every 20-25,000 miles. I have towed trailers in the mountains with some of GM's worst-reputation automatics without one failure (like the THM Metric 200 and the early THM 700R4) and attribute this luck to LARGE aux coolers and regular fluid changes. As was said earlier in a post, heat kills automatic transmissions and fluid starts to break down at 200 degrees. An aux cooler will cool fluid way down, the standard in-tank coolers are only going to get fluid temps down to the temp of the coolant: 190 degrees min. I expect the Volvo trans with the cooler I have (24,000 GCVW rating Tekonsha stacked plate design) to go at least 200,000 miles without problems. At 60,000 when I changed the fluid and dropped the pan there was less than a teaspoon of friction material in the pan and NO varnish anywhere. The same was true for my GM vehicles which were well known to show heavy varnish and lots of friction material in the pan even with 25,000 mile changes WITHOUT an aux cooler. Even the optional factory HD in tank coolers are not adequate for these vehicles (trucks) and many a campfire story would prove.

    Finally, don't believe the old wives' tale that you can overcool tranmission fluid in the winter. That's why you install it in series with the tank cooler. This will actually help warm the fluid a little in winter before it gets to the aux cooler. We had several mornings this winter here in New England where the temp was -15F or below. The tranny in my Volvo worked fine.

    Good Luck!


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    How can I fully drain the automatic transmission fluid.

    Date: Thu, 8 Apr 1993 08:58:23 -0500
    From: Juan Moran <moran@uxh.cso.uiuc.edu>
    To: swedishbricks@me.rochester.edu
    Subject: Fully draining Auto Transmission & Putting Magnet

    There is one way to fully drain the automatic transmission fluid.

    Disconnect the line that goes from the transmission to the radiator at the radiator end.

    Put a rubber hose onto the end of the line. Ruber hose should long enoguh to where you want tp put a bucket big enough to contain 10 quarts. If it is a one person job then you may want to put the buckect right by the driver's door.

    Have 9-10 quarts of automatic transmission fluid opened and ready to go.

    Place the long funnel to add trasnmission fluid.

    Start engine

    Auto. transmission fluid will start coming out at the radiator end.

    As it comes out add new transmission fluid.

    Once transmission fluid comes out clear turn off engine. Connect radiator line back. Add more fluid if necessary.

    In this way the whole automatic transmission fluid is new.

    So as to collect the metral shaving from the automatic transmission fluid one can olace one or two magnets around the drain plug. These magnets are the size of big quarters(2-3 times the size).

    Juan Moran

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    How can I tell the difference between a ZF unit and the AW unit?

    Date: 22 Apr 1993 22:37:49 -0400 (EDT)
    From: V093P9MD@ubvmsb.cc.buffalo.edu
    Subject: Re: tranny I.D.
    To: swedishbricks@me.rochester.edu

    The differnce between the ZF unit and the AW unit is easy to see. If you have a little switch on the side of the shifter knob, you have the AW series. The ZF lacks this knob. Also, the ZF shifter can be moved from D to 3,2,1. I think (not shure though) that the AW only has D to 2,1. The AW 70 and 71 are very similar, the latter is a slightly beefed-up one to deal with higher loads (like the 2 differnt OD units for the manual tranny). The turbo's get (for obvious reasons) the AW 71. The ZF unit was used at first exclusively on the Turbo Diesels, and later for the B230 (naturally asperated). Volvo sort of played muscial trannies as I think that the 760's have had both the AW and the ZF units over the years.

    I am presonally very pleased with the ZF unit in my 760 TD ('84), it is very smooth, and very responsive, but never jerks or hunts for gears. BTW recent Range Rovers have gotten the ZF22HP4 unit also, it is rated for 8000 LBS. towing, that should be a good indicator that it is plenty tough to deal with the low output of the B230's, or the D24T's.

    Happy Motoring,


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    How do you replace the rear main seal?

    From: alfred@nyquist.bellcore.com (Alfred Kwan 21342)
    Subject: Re: Tranny rear main seal
    To: maj@frame.com (Michael Jue)
    Date: Tue, 14 Sep 1993 09:45:19 -0400 (EDT)
    Cc: swedishbricks@me.rochester.edu

    > I'm tired of the drips in my garage (not to mention the lost oil.)


    Well, I did 2 of these in the last few months - a 240DL and a 745Turbo. The 240 was leaky and the 740's tail shaft bushing had too much play. In both cases, I replaced the rear seal and the tail shaft bushing. You don't have to drop the tranny, only the rear over-drive housing. You going to need a new gasket for the rear housing. I removed the cross member and transmission mount in both cases. I used a small piece of 3/4" plywood and a floor jack to support the tranny by the pan. I didn't time myself; it took about 3 hours for the first time. The hardest part was removing the old gasket. What a pain that was.

    I made 2 tools from round aluminum stock on a lathe to remove and install the seal and bushing. I think the right size 1/2" sockets will also work. The bushing is something like 1-1/8".

    You might want to check your pan gasket for leak also. You going to drain the tranny for this job; it is a good time for a new pan gasket if you need one.

    Be careful with the 4 cross member bolts. The rubber transmission mount makes it hard to reinstall them. Use the floor jack/w plywood to position the cross member first. Don't fight; I almost striped one on the chasis side.

    In another Email, you mention that your AW71 shifts hard. Well, my AW71 also shifted VERY HARD - big clunk from 2nd to 1st. I replaced the down shift cable and adjusted it by a Volvo mechanics. It shifts much better now, still hard compares to our 533i. For down shift cable replacement on the AW71, I had to drop the pan. So, check the cable adjustment.

    Good Luck


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