In looking for a rattle on the back of my truck, I found the spare tire was loose. I also found something that concerns me terribly. The black paint is already burned off of the differential cover and I only have 6K miles on the truck. Going to get into the oil this weekend and see what it looks like. Half of the 5K miles has been while towing 8K. Is this thing getting that hot already, or is the paint just really cheap?

Also, I hear what I can only describe as a turbine spool down sound from the back of the truck at low speeds when the gas is off, both while the driveline is engaged or while clutched?

 

Don't drain the fluid!! Check it's condition and if it is as bad as some I've seen get it to the dealer.

 

I agree, let the dealer do the forensic investigation ASAP.

If possible watch them drain the lube into a pan for inspection and not the bottomless pit oil barrel.