A904 No driving anymore

Transmissions and Rear Ends

  1. BudW

    BudW Moderator Staff Member

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    I have taken apart almost new transmissions. The thrust washers are made of a few different materials and it looks odd (or looks wore out) but most thrust washers are usually still within specifications. I don't get excited about “worn looking” washers. Now missing fingers or embedded metal or other things like that, I do get concerned about.

    Something made of steel is creating the iron shavings. Check all parts for metal on metal wear. Check the planetary gears for looseness, and so forth. If you can't find an obvious source of the metal, then change the torque converter! If the converter came apart, there will be metal EVERYWHERE inside (in every passage, every bore and in every crevice). The fluid from converter goes to the transmission cooler, then as lube for all parts inside of transmission. There is nothing to filter the metal shavings out after fluid leaves the converter

    Take the governor off (behind the tailhousing. You don't have to mess with the four bolts with lock tab. The removal of snap rings and taking out the pin, it should slide off. Those weights should slide inside of their bores with little effort.

    77 FSM 21-103h.png
    When converter is in place, it should be about 1/2" (13 mm) in above picture. You will need to rotate the converter (a lot) while pushing on it (not hard). You should feel three distinct clunks as the three items line up. Make sure the front pump seal is well lubricated with ATF before inserting the converter.

    Before transmission removal, I like to take a bit of spray paint (sharpie, or whatever) and mark one of the flex plate lugs like this:
    77 FSM 21-104a.png
    How or what color doesn't matter. The four torque converter bolts will only all go in, in one manor. If you have two (or three) that line up, but not the forth, you have to stop, remove all bolts, rotate and try again (a big pain in the ____). A person could remove the flexplate, but that is also additional labor.
    Note: your converter WILL NOT have a drain plug. Your converter might have a "V" stamped in it (in place of the drain plug) - but sometimes that mark is not present, either.

    Hopefully you found a detailed service manual for this transmission.
    BudW
     
  2. SixBanger

    SixBanger Well-Known Member

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    Thank you guys for lots of information and thinking. It helps a lot. Until now, disassembly was good to do.

    Sorry I don't get it. Is there kind of pin for locking the 'output shaft to forward drum' washer (the little broken one) lost in my transmission? On the web or PDF I can't find a clear exploded view of the outputshaft assembly of the a904 (only 727).

    1.PNG

    So far I have checked the front pump assembly. No metal shaves in the pump. Some damage on the bushing of the pump to TQ hub. I replace this anyway, but not real concern. But should double check TQ on cracks and surface.
    Should check the other parts for looking for metal shaves or worn parts.

    IMG_20190908_225422.jpg


    Here are shops that can do flushing the transmission. But is it also possible to flush only the torque converter?
     
  3. BudW

    BudW Moderator Staff Member

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    The A727 and A904 are built very close to the same (other than A727 is physically larger in most aspects). The pictures can interchange in most cases.

    Yes, but it will need to be taken to a torque converter shop to do so. The converter shop by me will cut the old converter in two to clean it and replace any worn/damaged parts, then re-weld and balance it. Many times, they will replace the starter gear (if worn or damaged). It is like getting a new converter at a fraction of the cost – but it takes about a week to get that done (or at least with the shop close to me).

    iuGLG109VC.jpg
    These parts run very tight clearances.
    Cheb TC.jpg

    Note: if a (any) bearing inside of the converter fails, then the moving parts inside of the converter will make a lot of noise and parts will contact against each other, producing a lot of iron shavings (like what you have).
    If you can’t find a source of metal shavings, then a bearing failure inside of converter is all that is left to point a finger at. To reinstall a known bad converter will keep sending iron shavings into the transmission. The torque converter is the only part you can’t investigate (easily) and it is “assumed to be good” until all else has been verified “OK”.
    Many shops will automatically replace the torque converter no matter what the problem is, but I have a slight disagreement with that procedure. The problem for you is getting a replacement converter might not be an easy job.
    BudW
     
  4. SixBanger

    SixBanger Well-Known Member

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    Transmission looks ok. Might flush it.

    After couple weeks I have get the parts.

    But there are two sets of trust washer kits. One for 1960-77 (53670 TF6). Second for 1977-on (53671 TF6 A904 A998 A999). I have orded the second one because, car might from 1978 or 1979 and does have LU.
    But they sent me the kit from pre 77.

    I see a different between the small shaft washer of the two kits.
    Can I use this kit?

    1.PNG

    IMG_20190927_220327.jpg
     
  5. BudW

    BudW Moderator Staff Member

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    The lockup came out mid-year 1978. It does require a few more sealing rings.

    A person could order a non-lockup for a few years afterwards – but typically on a special order only basis.

    Back to your question, the sealing rings and press-in bushings do have some differences, as well as front pump. I don’t “recall” there being a difference on thrust washers. If there is a difference, it only affects one or two of them.

    The sealing rings look like:
    Sealing Ring.jpg
    More specifically have the metal hooks on end:
    Sealing Ring a.jpg

    I don’t think the difference you have is with the sealing rings, though.

    If your thrust washers (the ones that don’t match up) only have minor wear, you might be able to reuse the old ones without issue.
    BudW
     
  6. SixBanger

    SixBanger Well-Known Member

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    Couldn't find a electrical solenoid in the trans that is used for activating the lock-up. So might be a early non LU transmission in this car.
    Yesterday install everything in the trans. End play measured at the front shaft. 0.060 inch, that is between the marges of 0.022"- 0.9"ish.

    Build in the trans today. I will see if it fixed the problem.
     
    Last edited: Oct 5, 2019
  7. SixBanger

    SixBanger Well-Known Member

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    Installed the trans with add ons.

    Still no drive in any position. Hearing again the whining sound. Can't define if it is TC or trans.

    Maybe it is usual to wait a couple time with running engine in Neutral to get the oil around the system?
    After +-10 min running the engine so far oil level seems high. I have added 4 liter with a ish full TC while installed (spilled some fluid with installation).

    The connection between outer teethed disk of first planetaire gearset and second clutch seems the same as before rebuild. They are connected.

    When connecting TC with flexplate, I did have to push the torque converter quite far forward to mount it (length of the mounted bolt). But I can see there is some play needed while installed on the splined axis of the transmission pump.

    Any help welcome.


    IMG_20191005_181548.jpg

    IMG_20191004_230027.jpg

    IMG_20191005_105159.jpg
     
    Last edited: Oct 5, 2019
  8. Aspen500

    Aspen500 Well-Known Member

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    The lock up is mechanical/hydraulic through the main control valve body, there isn't a solenoid. On the valve body, there will be a tube going to the "lock up module" at the back of the valve body.

    It almost has to be a problem with the TC or pump assy. The only way to really know is to hook up a pressure gauge to the line pressure port (one of the plugs on the side of the trans) and see if there's pressure or not. If there is, it leaves the TC, if not could be something broke inside the pump. The pump drives off the slots on the TC hub.
    There is normally 1/4" to 1/2" of play between the TC and flex plate when the TC is pushed all the way into the trans. If the clearance is too much and it disengages the TC drive hub from the pump tangs, then it'd be a problem but your car was fine before the trans failed.

    Did you take the pump apart and inspect the internal parts? It's rare but I have seen trans pumps fail suddenly in the past. Sounds like you went through the trans internals with a fine tooth comb so they're OK. Only thing I could think of is to get the converter tested but that takes a well equipped trans shop so it's easier said than done.

    Edit: I now see you did look at the pump. Missed a few posts before your last one.
     
  9. SixBanger

    SixBanger Well-Known Member

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    Thanks Aspen.
    Okay. I would look if i can measure the line pressure. Maybe seeing if there is some oil cumming from when loosing the hose a bit. Do you maybe know a range where the line pressure should be (to cooler)?
    Play between TC and flex plate was more than 1/2". But yes before no problem with trans.

    I have some pics of the pump assembly. Only there I had replaced the bushing from TC hub to pump. As a green hobby guy on transmission, my eyes doesn't has seen some abnormalities on the pump assembly.
    Surfaces looks ok, no cracks and slots to TC hub are ok.

    I only measure a little lower rpm of the engine when going from neutral to R. So there should some fluid going around the trans?>

    IMG_20190908_225242.jpg

    IMG_20190908_225245.jpg

    Naamloos.png

    When the trans was disassembled. I did put the input shaft into the TC. I notice when it slides in and turn it around in the TC. But maybe the depth of connection with the transmission could be effective?
     
    Last edited: Oct 5, 2019
  10. SixBanger

    SixBanger Well-Known Member

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    Chrysler A727, A904 Pressure Ports

    Did have found something


    Line Pressure in Reverse
    • Idle: 145-175 PSI
    • Stall: 230-280 PSI

    Line Pressure in D21
    • Idle: 54-60 PSI
    • Stall: 90-96 PSI

      I guess 1/8" npt fitting?
     
  11. Aspen500

    Aspen500 Well-Known Member

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    I believe it is 1/8" npt threads. Pressure at the cooler line isn't that high but it would tell you whether the pump is pumping though. I've never measured it but it's around 20-30 psi at the most.
     
  12. BudW

    BudW Moderator Staff Member

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    There is not a solenoid (electrical or other) that controls the lockup for FMJ vehicles (that I’m aware of). There is for fuel injected pickups/vans there, but not for FMJ’s - that I have ever seen.

    My ’86 M-body FSM (Factory Service Manual) shows there to be an optional lockup solenoid – but the electrical wiring diagram shows nothing. I looked to see if California Cars might be an issue – sense I hadn’t worked on that many California Emission cars.
    BudW
     
  13. SixBanger

    SixBanger Well-Known Member

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    Today I have measured the line pressure


    a.PNG

    b.PNG

    For D21:

    Idle: ~80 psi (5.5 bar ) Recommend 54-60 PSI ; higher
    Higher speed (~2000 rpm) 87 psi (6.0 bar) Recommend 90-96 PSI ; lower


    For Reverse

    Idle: <230 psi (<16 bar) Recommend 145-175 PSI ; higher
    Higher speed (~2000 rpm) >250 psi (>17 bar ) Recommend 230-280 PSI ; In between recommend pressure

    No check of oil to cooler so far. But when removing both plugs to measure the came a good amount of oil out. Notice when unscrew the plug for D21, that the plug was hand tightened (maybe dutch translation for not so stuck).




    Here a check list. Green lined is what I think is not the direct cause.

    - Worn or faulty rear clutch. Saw nothing special when dismantling. Seems new.

    - Worn or faulty front clutch. Saw nothing special when dismantling. Seems new. Same as rear one.

    - Worn or broken reaction shaft support seal rings. I guess this is the o-ring of the oilpump to casting? This one is new and no leaking so far.

    - Overrunning clutch not holding? I did saw no strange things or missing springs or whatever. Rear shaft spins free.

    - Valve body malfunction or leakage. I did not want to mess with this part because I put in some other parts. Saw no broken springs or other parts missing. Always smooth shifting.

    - Hydraulic pressure too low. Only measured low pressure on higher rpm on D21 pressure line.




    So TC can still be broken or not engaged to cause no drive because measured oil pressure?

    Knipsel.PNG
     
  14. BudW

    BudW Moderator Staff Member

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    This is from my '77 FSM (Factory Service Manual) - with any differences noted from my ’86 FSM.
    77 FSM 21-38g.jpg

    77 FSM 21-38h.jpg

    77 FSM 21-38b.jpg

    77 FSM 21-38c.png

    77 FSM 21-38e.jpg

    77 FSM 21-38f.png

    77 FSM 21-55b.jpg
    Test Four (from ’86 FSM) says:
    (4) Rear servo pressure should read 145 to 175 psi with throttle lever forward (at rest) and increase gradually to 230-280 psi as throttle lever is moved rearward.

    77 FSM 21-55c.jpg

    77 FSM 21-55d.png

    77 FSM 21-55f.jpg
    BudW
     
  15. BudW

    BudW Moderator Staff Member

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    @SixBanger Are you still having problems? If so, what is it doing exactly?

    That would be correct for lines non-lockup (early ’78 and older) transmissions.
    Cooler line pressure for lockup transmissions can be as high as 90 psi, when in lockup mode.
    BudW
     
  16. SixBanger

    SixBanger Well-Known Member

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    Thanks Bud. I would re test with these steps. So given engine speed and also on 1 and 2.
     
    Last edited: Oct 8, 2019
  17. SixBanger

    SixBanger Well-Known Member

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    I still have problems with the transmission. No drive in r,d,2,1. After rebuild, first start, checkt fluid level, let it run for couple minutes in Neutral. Then I did tried to shift to D or R. It was happen in a couple of seconds, but was thinking it shifted (engine get some lower rpm), but then no drive. Same sound as before. Some whining sound. But after that, I did not have heard that sound again. After shifting in all gears there is no difference in rpm of engine or load by just hear the sound.

    I would test it again. But I am almost thinking that it result in, Test Result Indication number 2; low pressure in D,1,2 but high pressure on Reverse. But again would check pressure in 1 and 2.
     
  18. SixBanger

    SixBanger Well-Known Member

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    When testing, shifted to reverse, I could record the whining sound. Now it is louder now than before.

    In the testing procedure they called, testing with throttle lever forward and gradually increase (should raise pressure). Is this like operating the kickback linkage to the throttle body? Or do I have to remove the locking nut on the transmission en operate it by hand? Sorry but can't see definition of put throttle lever in forward or rearward position..

    throttle.png
     
  19. BudW

    BudW Moderator Staff Member

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    I'm at work and can't pull up the video (work has it banned).

    I’m “thinking” the problem might be inside of the torque converter.
    For a “won’t move” concern, there is no difference between any forward gear or reverse. Moving shifter into 2 or 1 rarely makes any difference. From a standstill, “D” and “2” breakaway (initial takeoff) use all the same parts. “1” has one additional item engaged (otherwise the same as “D” and “2”), which is the Low/Reverse band.
    If it is not moving in “R” or “D”, then it’s not going to move in “1” either.


    When you have the transmission out, did you insert this item inside of the torque converter and rotate?
    IMG_20190908_225242.jpg
    Checking to see if you could feel it moving something, for noise and for play?

    You said:
    If you moved the input shaft, could you fell it moving parts inside? Could you notice any play and for any abnormal noise?
    A518 Input ShDr.jpg


    The torque converter hub uses the bushing to keep things “steady” and it also runs the pump. The front pump is working, or you would not have any oil pressure.

    The Top picture (above) splines into the stator. The stator has a one-way clutch which if failed (or splines inside stripped out) can cause your problem.

    The input shaft splines to the turbine (bottom picture). If the turbine splines are stripped out, then no power can be transferred to the transmission. With the amount of metal inside of transmission, I think one of these internal splines has stripped.

    Did you do anything with your old converter (send out to get cleaned or get it replaced)?
    BudW
     
  20. SixBanger

    SixBanger Well-Known Member

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    Last weekend I did install the old converter back in the transmission.

    I agree that the problem should be in the torque converter. But just to be sure it is not in the valve body.

    When the TC was out of the car, I only had tested with putting in the input shaft. It fitted easily and moved with some force. It did make some noise of turning around some fluid, but doesn't know if it is to much. No vibrations or very loose fitting when turning. So connection to the turbine could be made. But can't call how deep it grip the internal splines to the input shaft.

    I did not tested the bigger splines axis of the pump to the stator of the TC. So can't recal on that. But if broken splines or clutch, I can be wrong, but there is not directly related to get the vehicle start moving in D or R? More like faster acceleration for short time after dead-stop on the road and get moving again?

    I am thinking out loud. If there was some mechanical play between input and outputshaft. This lead to that the Trust washer between these shafts get bend and get stuck in between. And over time or when accerelation and deaccerlation caused to a broken ring in the TC. Like friction between outside of inputshaft and TC turbine connection. This maybe cause to friction on turning turbine and bearing and so overload on splines in TC?
    I was thinking this, because when reinstalling the TC on the engine I had to move the TC more length than the flexplate bolt. So this was more like 1/2" of movement. Maybe a new TC with fresh turbine could make the connection to the inputshaft. (I hope you can follow my description of the 'thinking out loud')

    Today I found called a company here that could rebuild a TC of alot of usa cars. So he said he look in to it and replace parts that needed. For same/lower price that new converters.

    But to not break a TC again in the future I want to be sure what cause this failure.