T-90¶

The T-90 is a 3 speed transmission with a casting number of T90 and a 1 1/8" 10 spline input shaft. Length of input shaft varies with application. Output is 1 3/8" 6 spline. The T-90s used in 1945 and some of 1946 where column shift. Later versions were floor shift like in the picture.
Drivers side view of T-90 with Chevy adapter. This adapter is the factory adapter that was used with the T-86 and Dauntless Buick 225 V6 engine. Most likely, the transmission is a T-90 case that has been rebuilt with T-86 internals. Many parts interchange between the transmissions.
This T-90 is out of a '50 CJ-3A. This is a typical aftermarket Chevy adapter. This adapter and the adapter above bolt to standard bell housings used in Chevy, Olds, Buick, Pontiac, etc. The bell housings used in these vehicles is the same on the transmission side.
Usage¶
The T-90 was used in CJs from 1945 to 1971. It was also the standard 3 speed in the Willys Wagon, Willys Pickup, M38, M38A1, FC trucks, and Jeepster/Commandos during this time period. The only variation are the T-86 and T-14 used behind Jeeps equipped with the "Dauntless" Buick V6.
| Transmission | 1st | 2nd | 3rd | 4th | 5th | Rev |
|---|---|---|---|---|---|---|
| T-90 (CJ version) | 2.98 | 1.66 | 1.00 | N/A | ||
| T-90 (PU version) | 3.44 | 1.85 | 1.00 | N/A | ||
| T-90-J | 2.798 | 1.551 | 1.00 | 3.798 |