Rear Axle Shudder

[chevydriver37]

Backed out of a parking spot tonite and the rear end on my 07 Sierra 4x4 started making a shudder that's similar to the one you get in the front if you turn sharp with 4WD engaged. I have the 3.73 G80 locker. I didn't have 4WD engaged, nor did the rear wheels slip or spin.

 

I know the rear end clunks/clangs/bangs/kicks, etc., when the locker engages, but a shudder? Anybody else experience this?

 

Thanks

[98 Z71 SLT]

I've been studying the G80 lockers recently...it sounds like your rear axle is locked, but is NOT unlocking.

 

Jack up the rear of truck. Put the transmission in neutral. SLOWLY, turn either rear wheel half turn clockwise / counter-clockwise. If your other rear wheel rotates also during these slow rotations, your G80 is broken, and the axles are locked.

[Scotty-B]

Did you recently do a gear oil change? Could be the type of gear oil causing the clutch pack not to slip properly?

[chevydriver37]

Thanks for the replies... I had the same issue this morning, as I was pulling into work, so I called to the GMC dealer right down the street and told them what the problem was. They gave me a ride to work, and towed the truck. 4 hours later dealer advises they changed lube and couldn't duplicate the problem. I didn't change the lube in the rear, as I only have 6400 miles on her. No clue why this happened.

 

Another thing that sort of burned me more than the breakdown itself, was that this dealer didn't seem to awful interested in helping me out, until I told him that it would barely move. I understand that you're supposed to go to your originating dealer for service, but I was under the impression that drivability/emergency issues would be handled by any GM dealer. I considered my truck shaking off the frame a drivability issue...

 

Rick