pinion nut torqued to about 150-200 pounds and modest resistance to rotate the pinion. something like 20-25 inch pounds?

 

sooo turns out it was the brakes....had no problems with them before we started the overdrive work, and they looked ok...must have stretched a spring or something when we were taking the pinion nut off.

I replaced all the hardware on both sides and it's running great now...at least now I can sleep better knowing my pinion yolk is on correct now though...

 

Glad you got it and happy to hear that it wasn't in the differential. That can get expensive real quick.