The problem with mine was the pinion bearing. It has since been replaced and the loud hum is gone. It was actually cheaper than expected, until the mechanics decided to convert my driveshaft into a one piece without notifying me until I came to get the vehicle. They said there was something wrong, warped maybe, but I still don't understand why they replaced my driveshaft. That move cost me about 50% of the total cost, and I'll have a talk with the boss come monday. I just hope this move will not screw more things up.

 

Just changed rear u joint and lined things up (before and after) There is a slight vibration around 65 + mph so I drive 60 and below. Could I have mismatched the rear diff flange to the DS flange? Would that make a difference? Lube shop said they greased everything but I didn't notice any grease when I unscrewed the spline zerk to check. Would that make a difference? Have a nice 1400 mile trip on Tuesday and it doesn't do bad at 55. Any hints?