Vehicle: 98 GC Laredo, 5.2L, AWD, Up-Country Suspension, Tow package. 200,000 miles.
I have had a mild whine on acceleration at 45mph+. Also had a vibration at that speed that was bad enough to jiggle the rear-view mirror.
Fresh fluid in diff and TC. Didn't look bad a year ago when it was changed other than darker.
Took out front driveshaft, the ride is as smooth as a car, no noise.
Replaced all u-joints and centering-ball in double cardin setup. Now, there is only a slight vibration at 45mph+ (mirror is still). The whine didn't change.
The guy at driveline shop said that the shaft didn't need balanced. I usually do, but he said it was overkill, based upon the normal rpm range shaft rotates.
Vibration may be a little worse on deceleration, but maybe just notice it more since you don't feel the engine torque.
Based upon what I have read on other threads, the noise is the pinion bearing. Would you agree? Or is it a bearing on the output of the TC? Or was it a mistake not to have the shaft balanced?
I guess what is confusing to me is the noise + vibration. Or am i fighting two issues here and i just eliminated the 3rd by replacing the u-joints? Thanks!