[Doug Linden]

The units that use the splined coupling between the output of the OD to the pinion stub shaft are the preferred arrangement. I believe this modification of the Borg Warner unit was designed by Bill Swigert in Washington way back when. Bill's design also used all of the factory electrical controls (solenoid and governor) to make its operation easy. I think there was a fellow in Ohio who made the units with the chain connection and used levers to control the operation. I ran a BW overdrive for 30 years and it worked fine.