when setting up the new pinion in my housing the shaft starts getting hard to turn at just 45 ft/lbs. Using new inner and outer bearings and crush tube. What could i be overlooking ?

 

Inner pinion bearing spacer problem. Are you using the one that came with 3.6 or the one from the pinion you took off? I didn’t realize there was already one on mine and stupidly put the old one on top of it. Locked up way too early and my ring paint was never even close till I figured that out. I think my thread on the same swap was about a year ago. Red arrow points to the the spacer I’m referring to. I suggest you start with the one that came with the differential rather than the one that might have come on the 3.6 pinion.