It may be differentials...although, I did just have the differential serviced, the oil changed, and I specifically asked if they saw any metal in the old oil. They said it was clean....Thanks guys
After I shift into third, I can hear an odd whining noise from the rear...sometimes if I let up on the gas it goes away..sometimes it doesn't. Typically though, if I take it up to speed and then let it cruise a bit, the sound goes away. Any thoughts?