I would probally let them replace the rear end housing if it were me. I have never heard of any others doing that though!
Is the truck a 4x4? If so you might want to have the transfer case oil pump inspected, there is a clip in there that can break and rub a hole in the case causing all the oil to drain out and then totally trash the case befor you even know it, usually the first sign is the output bearing gone! There is a kit to fix this from hapening but if the case is allready damaged it will need fixxed first!
Transfercase fix kit-
Transfer Case Pump Upgrade Kit