A904 Rear Planet and Other Questions

[77aspen]

For my first transmission rebuild I got a 1968 A904 from a junkyard, so I don't know the history. Pan rail is PK2892080Z 2621 3994. Been reading lots of threads, this site is a wealth of information.

First, is there supposed to be a flat steel washer between the rear planet and ring gear? There is a machined pad on the ring gear, red dot, but no washer present on the forward or rear planets. They are aluminum with 4 pinions.

Anyone ever use one of these? ATI TF904 Output Shaft Bearing Kit #904207, ATI Racing Transmissions - Chrysler Torqueflite TF904 Drag Race Transmissions , Do they work better than the fiber washer?

Thanks,
Robert

 

[Duane]

For my first transmission rebuild I got a 1968 A904 from a junkyard, so I don't know the history. Pan rail is PK2892080Z 2621 3994. Been reading lots of threads, this site is a wealth of information.

First, is there supposed to be a flat steel washer between the rear planet and ring gear? There is a machined pad on the ring gear, red dot, but no washer present on the forward or rear planets. They are aluminum with 4 pinions.

Second, is there an off the shelf bearing driver for the reverse drum? It measures 2.05 od and 1.95 id, I don't seem to have a driver that size, have the harbor freight 10 piece and the other one that goes up to 1 3/8.

Anyone ever use one of these? ATI TF904 Output Shaft Bearing Kit #904207, ATI Racing Transmissions - Chrysler Torqueflite TF904 Drag Race Transmissions , Do they work better than the fiber washer?

Thanks,
Robert

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The Ati bearing kit you are looking at is a bearing to go between the input shaft and output shaft. I recently purchased a 904 input shaft from Ati and the input shaft has a machined recess to use the roller bearing part number you quoted. In other words the bearing you are looking at is not a replacement for the larger fibre washers that go between the drums. The Ati bearing you quoted is only about 1 inch in diameter. It is only to be used if you have an aftermarket input shaft from Ati.

To answer your second question, no there is not a thrust washer on the back of the rear planetary because it is an aluminum planetary.
Aluminum is a compatible metal with steel so Chrysler did not use them on the rear of their aluminum planetary. If you assemble the rear planetary into the ring gear you will notice that the machined raised section in the ring gear makes contact with a raised section on the back of the planetary. All by design.
Hope this helps.

Duane

 

[77aspen]

Duane, thanks for the info. I was confused on the planetaries since the 727 videos I was watching on youtube had something behind them, and even the ATGS showed a thrust washer.

On the ATI kit I could have worded that better. I was wondering if you can use that with a stock input and output shaft or if you need one from ATI. I looked on their site and even downloaded the catalog and could not find instructions. Can you tell me if their input shaft differs from the stock one? My output shaft has a boss that is about .350 in diameter and .150 tall and the input shaft has .375 diameter hole drilled about .250 deep.

 

[Duane]

Duane, thanks for the info. I was confused on the planetaries since the 727 videos I was watching on youtube had something behind them, and even the ATGS showed a thrust washer.

On the ATI kit I could have worded that better. I was wondering if you can use that with a stock input and output shaft or if you need one from ATI. I looked on their site and even downloaded the catalog and could not find instructions. Can you tell me if their input shaft differs from the stock one? My output shaft has a boss that is about .350 in diameter and .150 tall and the input shaft has .375 diameter hole drilled about .250 deep.

Here is a picture of Ati input shaft. It is actually double rollered.
I could not find the thrust bearing right now but you can clearly see that the shaft from Ati is clearanced for the extra thickness of the other roller bearing.
You would have to modify a stock shaft to use the thrust bearing and the pilot bearing come pre installed in the Ati shaft and is not available for purchase separately from Ati.

Duane

 

[77aspen]

Duane thank you again for the great information and picture. That clears everything up for now.

Robert