Thanks for all the help so far. The engine is strong and the only sound it makes at highway speeds is a high pitched whine. In my opinion the rear end must be geared for farm work and not highway speeds. i saw a kit on the chevyduty page that would remedy this problem, but ti states it needs to be installed by a pro. does anyone know is there an alternate rear end I could swap to to allow me to cruise at 60 or so? Or do I need to get the kit installed from chevy duty to ge tthere. I have not tried the jack it up and spin the tires trick yet, but I am replacing the rims that are on there for stock ones and I will try that then just to see exactly what rear end it is.
