904 Transmission

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shouldn't be much from an exterior or swap/use point of view.

Internally they will be different.
 
The later trans will have the part-throttle kickdown, the earlier may not. They are pretty similar and will interchange.
 
front servo is different after 1972....suppose to be better.
 
superdave said:
Will it operate correctly in my 69 dart?
Thanks!
Dave
Click to expand...

Yes it will work fine.

70aarcuda said:
front servo is different after 1972....suppose to be better.
Click to expand...

Chrysler said it is better but in reality it's not from a perf. aspect. I always install the early servo in a perf. application. Quicker apply and release of the front band.
 
The pre72 trans uses a smaller tailshaft seal that can be difficult to find. The 75 trans has better internals more easily adapted to a 5 disc front clutch drum. The planetaries will also be steel caged instead of aluminum. Are they better? I don't know.

Yes the servo is different also. Turbo Action recommends the use of a 72 or later 904 for any performance application.
 
Hi guys , I am new at this forum stuff so if i placed this in the wrong section sorry,
I just acquired a 64 dart convertible with a slant six and a 904 pushbutton tranny, i drove it for about 45 miles then yesterday while driving the trans locked up temporarily when it shifted to second gear it almost felt like the trans went from first to reverse then back to first??? It could be that the trans just locked up temporarily, it happens to fast to stick my head out the window and investigate further
Does anyone have any idea what could have caused this problem? Prior to this new situation the car shifted fine? Last night I bought a used 904 with a recent rebuilt from a 73 duster and when i got it home and the car on stands I realized that the shifting mechanism will not work, , the tailpiece is longer and the park lever has no way to attach to the newer trans.
Can I swap out the insides of the older for the newer parts and use the original casing? I need to have this car running today for a job in the next few days so Any help resolving this would be greatly appreciated.
Oh yeah I just dropped the pan and there are some metal filings in the bottom , there are not a lot and not any big pieces to speak of, ????
 
maddogz said:
Hi guys , I am new at this forum stuff so if i placed this in the wrong section sorry,
I just acquired a 64 dart convertible with a slant six and a 904 pushbutton tranny, i drove it for about 45 miles then yesterday while driving the trans locked up temporarily when it shifted to second gear it almost felt like the trans went from first to reverse then back to first??? It could be that the trans just locked up temporarily, it happens to fast to stick my head out the window and investigate further
Does anyone have any idea what could have caused this problem? Prior to this new situation the car shifted fine? Last night I bought a used 904 with a recent rebuilt from a 73 duster and when i got it home and the car on stands I realized that the shifting mechanism will not work, , the tailpiece is longer and the park lever has no way to attach to the newer trans.
Can I swap out the insides of the older for the newer parts and use the original casing? I need to have this car running today for a job in the next few days so Any help resolving this would be greatly appreciated.
Oh yeah I just dropped the pan and there are some metal filings in the bottom , there are not a lot and not any big pieces to speak of, ????
Click to expand...

Hey Maddogz welcome to the board. You are in the right forum but you've posted in somebody else's thread. Even though it's the same subject it's best to start your own thread so it doesn't get confusing when somebody answers because you never know who the answer is for. You start your own thread from the main page of the forum you want to post in. On the upper left side of that page is a box entitled "new topic". Click on that box and a blank topic box will appear that you name what you want and describe you problem in. Hope that makes sense.

Anyway I'll do my best to answer you. It sounds like for some odd reason the rear band applied (it is only applied in reverse and when you manually shift the car) and it stayed applied while the front band applied. It's quite possible it was due to a sticking shift valve in the valve body or the rear servo piston jammed and stuck in place. In either case swapping in the internals from the newer transmission (which won't work) won't solve the problem. The main reason I say they won't swap is the input shaft has a different spline count so it won't work with your torque converter. Also if I remember right your 64 trans. utilizes a rear pump assy so parts in the back are different. If it just had a little metal in the pan that's not bad. Chunks would be bad. Alot of metal would be bad. The rear servo should be checked for wear allowing it to **** sideways in the bore. You may need a new low/reverse servo piston as they wear out eventually. Sometimes the bore is worn also and I think you can buy oversize pistons (.001~.005 over) to make up for it. If there's not a problem there it is most likely a sticking valve in the valve body. Since you have it apart take the valve body down and carefully disassemble it and check everything and give it a good cleaning. You might find a piece of metal or sludge in there causing a valve to stick and cleaning should fix it.

BTW: If you were manually shifting the car when the problem occurred something's causing severe overlap (that's when it's in first and second gear at the same time). That could be from the piston sticking or a valve body problem. Don't manually shift it until you get it fixed or it will trash the trans.

Feel free to pm me for my ph. # if you want to take about it more. Tracy
 
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