92 / 1500 gear problem

ok, here it is....

I get a whirring noise while under accelration and decelerating. No sound while coasting. I have replaced the gears (ring and pinion) I have fiddled with it so much i can get in and out of the pinion in less then 3 hours.... i dont have an arbor guage, just using a feeler guage....I am starting to think it may be the transfer case.

for you pros...the truck is a 1992 with a 350, th700r4, 4x4. it has about 108000 miles on it. replaced the tranny about 10,000 miles ago. I put the stock 3.42 gears in the rear and the rear end is the GM 8.5. 10 bolt. The gears installed are the factory gm...Not richmond or other off brand.
yes i have through a couple of crush sleeves!!!!!and if I have to tear into again, Ill have to replace another.....

thanks

anyhelp would be great......
Ron