I have learned that the vibration / grind happens when I am on a fairly flat road, highest gear, when going from steady cruise no load to a little throttle and pressure on drive line just before down shift I experience a vibration / grind. Feels like mid truck to rear. If I let off it stops, If I accelerate through it it gets a little worse and I feel a drag and then It goes away.
Its not a tire balance issue, obviously.
New bearings in rear axle and diff, new u joints,
Please help!

 

There may be a problem with the gearbox.

 

I finally got it on a lift and now I know it is in the rear differential axle somewhere I have a lot of end play on the axles but it seems more like the limited slip assembly is bad I hope that's what it is I'm going to replace it. I don't get too many replies and no one seems to have any advise so that's what I'm going to go with if nothing else I hope my problems help somebody else with a similar issue.

Mountain Mike

 

The gear mesh has to be right on within tolererance, and shimmed if need be to get the clearance. Thing called plasti-gauge will give you the mesh clearance. I'd not recommend this level overhaul.

 

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kevinkpk, are you referring to inside the transmission if so I agree I would never try that I really feel like it is the differential limited-slip assembly it is very loose back there and makes a racket

 

What rear end do you have? I'd say it's cheaper and easier to upgrade to a good used 14 bolt semi float than to rebuild a junk 10 bolt. Just my opinion.

 

yeah 8.2 is junk but the 8.5 is just as strong as the 14-bolt I would never spend all that time and money when I can just put a new differential in it.

 

Best of luck