I keep shearing off the support rod bolt on the belhousing. I am absolutely using grade 8 bolts. OEM trans cross member. Any ideas on how to stop this? I don't have huge tires, haven't wheeled it very hard.

I checked it like a dozen times, I am pretty confident its good. Guess I will grease up the drive shaft. What type of grease should I use? Don't want to contaminate the transfer case fluid.If the passenger weighs the truck down any, WOW, than your pinion angle should be looked at.
Or it's you bench seat that's loose
And I would agree, might be your slip. I should move freely.
weird thing but how is the motor mounts ? ?
I have seen them bad give a LOT of unwanted flex in the system . DO NOT buy o.e.m aftermarket replacements there junk these days and don't last at all.
also check the trans/t-case mount . even if you have to block of wood/floor jack it to try and move it . the rubber could be unbonded and still look o.k.