Chevy G506 transmission

[retro-roco]

Can anyone tell me if the '42 Chevy G506 used the same four speed transmission as the civilian 1-1/2 ton truck?

I have found a tranny, and it looks very much like the one in my truck. The part number is 590957, or the case casting number is 590474. I am out of town, away from my SNL and parts books. Please let me know if this is correct.

Thanks guys!

[42 chevy]

The civilian truck used a differant first gear (granny), as long as it does not have the parking brake attached to the rear of the tranny, it will work, direct bolt in.

[dr deuce]

The early Chevys had the same gear ratio tranny as the civy one. Later they made it a close ratio tranny and got rid of the granny gear as they had the low range. It probably also helped with the axle breakage problem that the Chevys tended to have if you got rough with them. The civy trucks would/could break axles with the granny 1st without the 2x transfercase ratio.

[retro-roco]

Thanks '42 and Dr.!

Both responses were helpful. What I am hoping to either confirm or refute is whether the transmission I have found is the "right" one, at least according to part number... I have one that is "right" but needs rebuilt, while this one is NOS. Of course it may be worth picking up just to have a spare. (Oh lord, how many times I've said that!) How many transmission main shafts will a guy realistically go through in one lifetime??