The Stovebolt Site Forums The Shop Area Driveline 37 and 40 rear carrier gear

Does anybody know if the pinion and ring gear and carrier from a 40 pick can be installed in a 37 rear (both 1/2 ton)?

At first gland the internal sizing looks compatible. The 40 has a thicker shaft and bigger caps for the internal axle bearing, but the bearing appear to be the same size. I did not get the 37 pinion out yet.

I was going to switch rears to allow a 3.55 gear. I have the u joint covered. The 40 rear tube is 1.5 inches longer that the 37. I either have to 1) cut the tube, 2) change the guts between the two (if possible), or 3) mount the rear axle 1.5 inches back of center on the leaf spring (which is more centered than original in the fender).

Any direction would be helpful.

Mike J

1940 was the first year for the Hypoid design ring and pinion in 1/2 ton's.
1940 also went to a finer spline on the drive shaft.
The 40 will have two different length axles and the torque tube is mounted off center in the axle housing.
The 37 will have two equal length axles and the torque tube is centered in the axle housing.
You can swap the whole thing but you still need to overcome the spline count problem. This can be done if you go this way.