Originally Posted by rbsj

The posts here got me duly concerned so I had my diff oil changed this morning by my local shop (they charged me $112 so it wasn't worth my time). Ran the car on the highway for about an hour ahead of time at 80 mph to get the diff oil hot before changing. At 33K miles no leaks on the diff, oil that was changed out looked like fairly typical diff gear oil to me, not sludge like. Upon pumping in the Motul 300 specified earlier in this thread and getting the car back on the road at 80 mph the rear seemed to have a little bit less hum (now that's scientific isn't it). Certainly not hugely noticeable, but good peace of mind. Thanks to all for posting on this.