You would save a bunch of cash if you swapped your driveshaft flange, unless you like having diffs rebuilt and reset. I know the right flange is availible because I had a driveshaft built here locally for a TII swap with the large axle diff and sent it to Japan for kenn chan. Driveshaft had a 3" diameter tube too.

 

Just to clarify for anyome reading,the pinion nut only affects the pinion bearing preload.Overtightening the nut will cram the bearings into their races and they will fail due to heat and friction.Leaving the nut too loose will cause the pinion to slop around,causing bearing failure and oil leaks at best........or gear/differential catastrophic failure at worst.

If you absolutely MUST pull the nut and replace it without resetting the pinion torque correctly,here is a suggestion.......
Assuming the rearend is setup correcty and is not damaged beforehand.....Tighten the nut down only to 94lb ft.This is the factory minimum torque needed to retain the nut in place and the starting point for setting up a pinion with a used sleeve.Its not enough pressure to crush the sleeve down and increase the bearing pressure beyond what it was before you took the nut off. A little looseness in the pinion wont hurt much,they get loose over time naturally due to bearing wear.So long as the pinion isnt sliding in and out of the housing,youll PROBABLY be alright.Too much torque on the nut is the real killer since the pinion spins at very high speeds and the preload pressure spikes tremendously even with only a slight twist of the nut.......so no impacts, please people!

 

So.. back on track.. The rubbing persists.. I've ensured the axles are fully seated.. but I still don't see how that could have been it (Isn't there a bunch of splined contact surface?)..

I do, however, recall that the original fill plug was not used... it looked like somebody had stripped the hole and re-tapped it larger using a different thread plug. This plug was a little deep.. Could it be rubbing on the ring gear around right hand turns? Its the only situation where the sound matches the possible cause... (in my head).

 

Also, I did not use a gasket, I used "the right stuff" by permatex... Worked fine in my jeep, so I figured it'd work fine here. Perhaps its like a water pump and you NEED a gasket for clearance issues?

 

Keep looking, neither one of those would do it.

 

G'damnit. Guess I'll swap out axle shafts this weekend with another car... that'll at least tell me if its the bearings.