A-904 Compatibility and changes?

C2ndLTpigeon said
Wanted to see if someone knows the difference in years of the 904?
For example rebuild kits will list 1960-1971 and 1971-1992.
Other than the obvious linkage setup on the outside of the transmissions what changed internally?

I have a 1971 /6 904 and 72 /6 904, yet the kit cuts of at 71 and the other starts at 72. Are the cases the same and just the internals?

Still learning automatic transmissions.

Thanks

In 72-73 the kick down servo diameter increased. In 78 the sealing ring diameter changed on the input shaft. Can’t remember the year, but the roller bearing on the output shaft changed dimensions. The wide direct drum used a front pump with a beveled back. Just a few I remember off the top.