The Army G506 truck used the same 4 speed transmission as the civilian Chevy trucks from 1940-1946; except for the output bearing retainer. The transmission model number is GKT-134. A lot of the early 40's trucks get restored with updated engines and drivetrains, so it should not be too difficult to find a donor transmission if needed. Most of the bearings are readily available, and as indicated, the gears are heavy duty, and will usually remain serviceable even if rusty.
