08 GMC Yukon Rear Noise and Clunking

08gmcyukon

Original poster
Member
Jun 10, 2021
8
Florida
Ive always had a whirling/humming sound coming from my rear end area, asked many friends about it and they always said "Man thats just your tires," which i knew it wasnt my tires because i drive it daily and know what my tires sound like. Well after driving with the humming sound for sometime, thing finally got worse. Now im at the point where while driving and slightly turning to the left it sounds rougher and louder like rubbing rubber and now its developed a clunk when engaging gears from park. So i decided to take the diffrential cover off and didnt notice anything abnormal, I replaced the axle bearings thinking that was the issue but the old bearings look fine. So now im assuming it maybe something to do with the pinion. The previous owner installed a leveling kit and added some 20X12 inch rims with 33 in tires, which i feel is part the blame because im sure its still running with the stock 3.42 gears. Any advice would be appreciated.
 

TollKeeper

Supporting Donor
Member
Dec 3, 2011
8,045
Brighton, CO
I would go in a completely different direction on this..

Its a common problem on the NBS (New Body Style - I own) and the NNBS (New New Body Style - you own)...

The motor mounts is where I would start, specifically the drivers side one. Open the hood, put it in gear, and with your foot firmly on the brake, and one on the gas, look to see if the engine moves as you press on the gas. It will sound like a humming, or drumming, or (enter descriptive word here). Mine has it too. Thought it was the front diff, but is the drivers side motor mount.

Is your model the one with full time AWD, or selectable 4x4? Another issue has been with high mile trucks in the AWD variant, and transfer case chain slop.
 

TollKeeper

Supporting Donor
Member
Dec 3, 2011
8,045
Brighton, CO
Im at 82000 miles.. and its a motor mount.
 

TollKeeper

Supporting Donor
Member
Dec 3, 2011
8,045
Brighton, CO
It's not that it's causing rear end noise, it's that is connected to the drive line. It's worth a check in the motor mount, it's a free and easy check.
 

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