What/how many bearings are there inside of my rear end (hold the laughter)? The humming is making me what to jam a sharp object in my ears! There is also a vibration that can be felt in the center channel that seems to be related to the humming. Any ideas on this?

 

Anyone? Where are the weights on the driveshaft to balance it?

 

Pinion bearings, carrier bearings, and axle bearings..... The humming could be from the ring/ pinion wear....

 

My pinion bearing was bad; it caused a constant "humming" noise. I had all six bearings replaced and also changed the ring and pinion to a 4:10. I just put it back in the car and have about 30 more miles to go for the break in period. She's real quiet now; I'm totaly impressed with the GM gears.
Your looking at around $150 labor to have the bearings replaced; a complete bearing kit will run you around $125 from Summit.

Good Luck