Just drove about 150 miles back to my house and I heard a squeaking rotational noise coming from the rear end when I started moving from a stop sign. I pushed the clutch back in and the noise went away. 1st and 2nd sounded the worst, couldn't hear it as well in 3rd, more wind noise and such.
When I got home, I slid under and felt the rear end and the temp felt warm but not too bad. The fluid level was good and its full of synthetic gear oil. I visually inspected the drive shaft and u-joints and everything looked and felt normal, the only warm spot was the drive shaft coming out of the transfer case (rearward). The transfer case felt about the same temp as the rear end.

Could I be losing the pinion bearing? Why only noise when drive train is engaged? Thanks for the help,

Conor

 

I think a u-joint is just starting to go bad. Give it a little time and it will be easier to tell.

 

Yeap, U-joint is on it's way out. Look for the redish dust, won't be hard to find.

 

Yep, just replaced my rear-most U-joint next to the differential.

I would say with 95% certainty that this is your problem.

Word to the wise - Remove the driveshaft yourself, but pay someone else to install the new U-joint for you! They are a PITA (more so than other trucks I've done).

 

Stay away from the baked beans...