Need 904 assembly help!

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gregsdart

gregsdart

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I have a 1972 904 serial pk35xxxxxxxxxx.
I am a bit confused about what thrust plates and washers go where. I assume there are no thrust plates or washers behind the rear annulus gear? Inside the rear annulus one diagram shows a thrust plate, but I don't remember there being one there, and there is a machined thrust surface already there. I assume next comes a four tang thrust washer, then the rear planetary,then another thrust washer with four tangs which goes against the thrust plate in the shell,thrust plate on the other side, then thrust washer with four tangs, next the front planetary. Then there is a fat thrust washer with one tang and a flat area on the inside that goes on the second gear planetary? If some one can verify this with a decent picture or detailed description, I would appreciate it. I have both the astgi book and Tom Hands book and still don't get a clear picture of what goes where. I have learned there have been many small changes over the years. I got the wrong tailshaft boot in a kit, and ordered a rear output shaft roller bearing and snap ring and got one that was about .060 too big! Arrr! And I measured the old one with a dial caliper for them when I ordered it. So, thanks in advance. I learn best with pictures!
 
If no one chimes in,i may be able to find the book with a decent breakdown tomorrow.
 
I have the ATSG for the 904 ....and 727....send me your email address and i will send it to you

hang on...steaks just came off the grill.........
 
You can download some / all of what you need. Wander over to MyMopar and download the whatever year service manual you need

MyMopar - Mopar Forums & Information - MyMopar Tools/Reference

Some of the manuals there came from the efforts of the guys right here, including the one for 72

So far as ATSG, you can download pirated ones from a Russian site I think they must have all of them

I started a thread on manuals........

Free service manuals

Go to page 2 post 41 is the info on ATSG if it "still works"

I also started a thread about a book I liked and it turns out the author, Tom Hand, and some of the contributors, are members here!!!!

!!!BUY THIS BOOK!!! ??
 
I have both books, thanks. Will check the links.
I just found a clear blow up of the gear train . Thanks for the link to the manuals!!
I have one too many thrust washers. None needed between the rear annulus gear and rear planetary !
 
gregsdart said:
I have both books, thanks. Will check the links.
I just found a clear blow up of the gear train . Thanks for the link to the manuals!!
I have one too many thrust washers. None needed between the rear annulus gear and rear planetary !
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You have an aluminum rear planetary correct?
I have seen many aluminum rear planetary with no thrust washer because you already have dissimilar metals. All steel ones would have a thrust washer as far as I know.
 
Finished my 904 last week. I can show you what a done one looks like. Start reading it's not that hard.

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Got the gear train together with .011 clearance, and notice that the only thing keeping the gear train from moving forward about a 1/16th inch will be the thrust washer between the input and output shafts, plus the roller bearing in the tail shaft. I assume that is normal and I didn't miss any thing. Thanks for the help!
 
Can't comment if you got all the parts in since I didn't see it go together, but basically the small thrust washer mostly sets the input shaft end play. As for the gearsets, there should be a snap ring that goes on the output shaft inside the case, in a grove in the shaft, to the hold the gearsets in during assembly, before that thrust washer and forward clutch go in. Nothing really big or robust holds the output shaft and gearsets together, so it may be correct. Study the exploded views to see where everything goes if needed. I don't currently have a 904 apart to get pictures, just a 727.
 
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Well, the siege continues! I figured out the output shaft and gear train so I wound up with .011 lash, in spec. BUTTTT, (!!) when I went to put the roller bearing on the tail shaft, I couldn't find matching snap rings for securing the bearing. I had one that was the same thickness as the groves, but when I put the snap ring on the inner grove, the bearing would cover up the other snap ring grove, Not allowing any room for the rear one. I found some thinner snap rings at an ACE hardware, and had to sand them down a couple of thou to get them both to seat. That bearing is the one that came off that output shaft by the way. It also has a smaller I'd than the. Bearing out of the 1968 vintage 904 core I have. Ok, so I put the output shaft into the case and assemble the gear train, install the snap ring, then install the tail shaft housing and secure the big snap ring onto the roller bearing. When I went to trial assemble the direct and forward cluthchs and drum, I literally do not have enough room to seat the pump all the way! WTF? I have a 12 inch dial caliper so I started measuring everything, trying to figure out what I have wrong. I could get the drum lugs deeper into the driving shell by trial fitting without the little output shaft thrust washer, but when I put one in place, the drive lugs on the drum are exactly deep enough to be even with the outer edge of the driving shell. That tells me at least I am seating the clutches properly, (or should be?) So I am not sure anything is wrong there. I put the pump into the case without the clutchs to measure what the correct depth would be for the pump when seated. I then pulled it back out, put the output shaft thrust washer in place, put a thrust washer between the clutches, and one on the pump housing per the exploded view in the book. When I put it all together, the pump won't seat, and is .180 too far out of the case! This means I have something screwed up by somewhere between. .140 and .200+++! At this point all I can think of to fix this mess is to buy a core that is fully assembled and was functional, and take it apart, measuring every depth of each component and thickness of everything till I find out what I have wrong. Any thoughts? I am going back out to the shop to sweep up all my hair I pulled out, and hopefully find what is wrong.
 
gregsdart said:
Well, the siege continues! I figured out the output shaft and gear train so I wound up with .011 lash, in spec. BUTTTT, (!!) when I went to put the roller bearing on the tail shaft, I couldn't find matching snap rings for securing the bearing. I had one that was the same thickness as the groves, but when I put the snap ring on the inner grove, the bearing would cover up the other snap ring grove, Not allowing any room for the rear one. I found some thinner snap rings at an ACE hardware, and had to sand them down a couple of thou to get them both to seat. That bearing is the one that came off that output shaft by the way. It also has a smaller I'd than the. Bearing out of the 1968 vintage 904 core I have. Ok, so I put the output shaft into the case and assemble the gear train, install the snap ring, then install the tail shaft housing and secure the big snap ring onto the roller bearing. When I went to trial assemble the direct and forward cluthchs and drum, I literally do not have enough room to seat the pump all the way! WTF? I have a 12 inch dial caliper so I started measuring everything, trying to figure out what I have wrong. I could get the drum lugs deeper into the driving shell by trial fitting without the little output shaft thrust washer, but when I put one in place, the drive lugs on the drum are exactly deep enough to be even with the outer edge of the driving shell. That tells me at least I am seating the clutches properly, (or should be?) So I am not sure anything is wrong there. I put the pump into the case without the clutchs to measure what the correct depth would be for the pump when seated. I then pulled it back out, put the output shaft thrust washer in place, put a thrust washer between the clutches, and one on the pump housing per the exploded view in the book. When I put it all together, the pump won't seat, and is .180 too far out of the case! This means I have something screwed up by somewhere between. .140 and .200+++! At this point all I can think of to fix this mess is to buy a core that is fully assembled and was functional, and take it apart, measuring every depth of each component and thickness of everything till I find out what I have wrong. Any thoughts? I am going back out to the shop to sweep up all my hair I pulled out, and hopefully find what is wrong.
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UPDATE!
I woke up and couldn't sleep, so I went out to the shop at 12:30 AM and tore into the tranny. I pulled it apart, removing everything but the output shaft. I checked everything and didn't find any of the components out of whack. Put it back together, dropped the pump in sans rubber o ring gasket, and wulla! The damned thing checks out with about .100 end clearance at the input shaft!! I am convinced I am haunted, plagued or it is just magic!
 
Well, I thought I had it done, but not so fast! When I torque the pump housing bolts, the rotating assembly locks up. I must not have had the pump seated all the way when I thought I had it together with plenty of clearance. I have a .068 output thrust washer, and two .064 thrust washers, one between the clutch retainers, the other on the pump. I can get a .052 to .054 output washer, but that won't give me enough room.
A quick recap; the output shaft roller bearing appears to be too wide, and I had to get thin snap rings, and then sand off a couple of thou to get them to seat. The front drum lugs are even with the outer edge of the driving shell, not slightly below surface like I expected. If I put the clutches in without the thrust washer as a test, the lugs on the drum go in farther like I expected, which tells me I am seating the rear clutch properly when I use the thrust washer like it is supposed to be. Is it possible this whole combo is just that tight on clearances? I can bandaid this deal a couple of ways, but I want it correct rather than do that. Comments, please.
 
Well, LOL, you must be getting pretty good at stacking the components into that case!!!
 
I would suggest removing the clutch discs and steels from the high/reverse drum only, leave out the intermediate band, leave off the large pump seal and gasket, then assemble everything else and see what happens. If your clearances are correct, your getting hung up on a clutch disc. If it binds up again, take out the thrust washer that is between the two clutch drums. If it binds again, put that washer back in and remove the small one between the forward clutch drum and gear sets.
 
Bobzilla said:
I would suggest removing the clutch discs and steels from the high/reverse drum only, leave out the intermediate band, leave off the large pump seal and gasket, then assemble everything else and see what happens. If your clearances are correct, your getting hung up on a clutch disc. If it binds up again, take out the thrust washer that is between the two clutch drums. If it binds again, put that washer back in and remove the small one between the forward clutch drum and gear sets.
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Bob, thanks for the suggestions. Last night(!) I put it together again without the output washer, and it works. So , I will make a custom washer maybe .040 ,which will give me an extra .028, which might make it. If not, an extra gasket in the tail shaft area will get me another .010.
 
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