BB 5:17 gears fit in 31 AA low speed axle?

[dhetch]

Has anyone put a set of BB high speed gears in a 31 AA low speed axle?
Thanks,
Dave

[Bob C]

The BB drive line is bigger than the AA so you would need to change the driveshaft and torque tube and
do something with the u-joints.

Bob

[dhetch]

Bob, thanks for your reply but my question is can the BB 5.17 gears be put in the existing 31 AA 7.25 housing. Some have said the BB gears can be put on the AA carrier, but I want to get this information first hand. It's a lot of wasted work if it can't be done.
Dave

[tiredtruckrestorer]

Dave, first the 30-31 low speed gearing is a 6.6 ratio for the bevel gear rear. I believe physically the BB 5.17 gearing will fit in the AA housing, but the pinion shaft has larger spline diameter and won't fit the AA driveshaft coupling. Like Bob said, changes would have to be done to the driveshaft. I believe the BB driveshaft has the female splines welded to the driveshaft itself and not a separate coupling like the AA style.

Keith