I wanted to run this by the experts on this forum. I have a 2008 TRD DC Auto. I am noticing when driving on the highway and I let off the gas there is a whining noise from the back of the truck. As soon as I even touch the gas peddle the noise goes away.In my experience this has been the differential. Any way I can test or verify? When I make sharp left turns I also hear a grinding noise. Dealer is no help since every thing to them is normal.