[rwdmayhem]

My parents have a 2002 GMC 3500 with the duramax. At highway speeds theres a rather high pitched whine that changes with how much your pressing on the throttle. It doesn't seem to make any boost till it hits about 2000rpm either but I can't confirm that as there isn't a boost gauge yet. The oil pressure seems unusually high as well around 70-75psi when cold. It does have 249k miles on it.