what are the differences between the P type and J type gearvendor overdrive units ? are they just in the output shaft and housings, or are there internal differences as well ? is the main unit used in volvo applications a lighter duty unit, or are these sections the same as used in the "normal" gearvendor kits ? i realize there are different mount holes and speedometer cable locations. i am looking for a unit i can make a custom adapter from 9" or so T-601 bar stock. also, what diameter and spline count is the "normal" input shaft ? thank you for your input on this topic.

bump..........

I would just call Gear Vendors, they are a friendly bunch in my experience.

https://en.wikipedia.org/wiki/Overdrive_(mechanics)#In_Europe

The basic design is the same, although the modern GearVendors units certainly have a higher torque rating than those found behind Volvo Fours.

The J type came first, the P type was the last design.

GearVendors bought the overdrive, lock stock and barrel. They are the sole manufacturers for a while now. They have uprated its torque handling capabilities.

It's a planetary gear arrangement which is hydraulically activated, like an automatic transmission.

I wouldn't advocate trying to adapt a Volvo unit to your hot rod.

R.