I was getting the clunking noise from the rear end about a year ago replaced the rear axle nuts and that took care of the problem but now I am getting the Whining noise from the rear end. Not sure if it’s the transmission or rear end. I changed the differential oil this weekend with the correct one ( 88862624). Did the figure 8 thing and drove it and the whining noise still there. I have a 2005-A-4 with over 120,000 miles on it. It appears that when the rear end gets warm from driving I can really hear the noise or I am getting paranoid about this whole noise thing. The noise has always been there it’s just seemed to be getting louder. Going to put it on jack stands this weekend and see if I can isolate where the whining noise is coming from. I read this on the forum that :
1. Whinning ==> differential gears not shimmed and aligned properly >> replace; Clunking ==> clutch packs sticking and breaking loose like hammer noise >> need friction modifier (up to two cans on later TB) (I'm assuming that we don't have loose joints or transmission problem); on friction modifier ==> do 10 or more tight figure-eights in parking lot to get friction modifier into clutch disks.
Anyone had this problem and found out it was the transmission or rear end gears that were bad. The car displays no other problems it drives fine, shift fine and hauls a_ _fine.

 

Sticking positraction clutches are clunkers, not whiners; so more figure 8's won't probably help. What you describe sounds more like a gear or bearing problem.

 

You might consider the torque tube bearings also.

 

Sounds bearing related to me

 

Check rear hub/bearings also.
When mine went bad is sounded like a diff issue.

 

What is the best way to check the hub bearing? In the old days you jack the car up and grab the tire at the top and bottom and see if there is any play in the wheel when you pull on it. I do believe it may be the bearing now that you mentioned it. I work on large vacuum pumps and they have 4 set of bearings in them and when they get bad they whine also. I got lot of work to do this weekend. I will be changing the water pump out on my 2000 Silverado. I think she is just jealous because of the time I have been spending with the Silverado that's why she start whining. Thanks for the information.