I just replaced my rear end with a used one. I replaced the axle bearings, axles, Rear diff cover, and the Ring & Pinion looked good. I had a problem with the tailshaft seal leaking, But I have since replace it. I think its holding up. However I am getting a cluck when I go to shift at high RPM (4K+) and occassionally I get a vibration... The vibration will come and go, but the cluck is kinda common...Something with the drivetrain, but Im not sure what to check. Ideas????