Just wondering how often are you guys flushing your diff fluid? I did it once with the GM stuff around 60k miles, just reached 80K and a very noticeably droning/whining from the rear started this past weekend.

I keep the launching/wheelhop to a minimum but still drive the car like it was made to be driven...just wondering if another flush after only 20k miles is worth it or just take it in to be looked at since I still have an extended warranty from my bank

 

Check it out with the extended warranty. They're a little worse to deal with than manufacturer's warranties though... especially if it's just a noise. If you can't get a new diff out of it, change the fluid. If that doesn't help then heatshield the diff from the exhaust.

Fluid changes have not seemed to change anyone's whining problems.
Heat shielding has helped mine and a couple others who tried it. There are plenty of naysayers that say heat has nothing to do with it, but I'm happy with my results.