Slight "thud" on moderate accel from standstill

[Bucky1]

Had it aligned today, and asked my buddy what he thought. He was leaning toward a driver's motor mount.

 

[09_4WD_YUKON]

I think I have the same thing as you, but have not checked mine out. I also think someone on here mentioned checking the rear trailing arm bushings.

Found my "thud"....broken driver side motor mount. Popped the hood, put it in gear and torqued the motor.....driver side lifted up. About to try out my Car shield warranty on it and have it changed with the H3 mount.

 

[Rocket Man]

Found my "thud"....broken driver side motor mount. Popped the hood, put it in gear and torqued the motor.....driver side lifted up. About to try out my Car shield warranty on it and have it changed with the H3 mount.

No warranty will pay to install a part that’s not a direct replacement. I’m sure they’ll pay for a Dorman pos or any other replica of the original part but the H3 mount isn't called for in any parts books for your truck. But maybe you can get a shop to swap the part out if you pay for the H3 mount.

 

[avalonandl]

At >100K miles, if you haven't replaced a motor mount, it is the motor mount. AND in the outside chance it is not, it soon will be, so replacing the driver's side motor mount with the Hummer mount will be money well spent.

I will check my motor mounts when on the lift again.

 

[09_4WD_YUKON]

No warranty will pay to install a part that’s not a direct replacement. I’m sure they’ll pay for a Dorman pos or any other replica of the original part but the H3 mount isn't called for in any parts books for your truck. But maybe you can get a shop to swap the part out if you pay for the H3 mount.

Took it to the shop. He called up Car Shield, argued with them over .2/hour of labor, finally said ok. They sent Auto Zone parts for him to change them. Not entirely bad, as I would probably have done the same. So, $50 deductible, changed both motor mounts and trans mount. Next time I will take it to a dealer for the repair and see what happens there.

 

[Doubeleive]

Took it to the shop. He called up Car Shield, argued with them over .2/hour of labor, finally said ok. They sent Auto Zone parts for him to change them. Not entirely bad, as I would probably have done the same. So, $50 deductible, changed both motor mounts and trans mount. Next time I will take it to a dealer for the repair and see what happens there.

the trick is when you want to use the parts you want then you "agree" the pay the difference in price for the part, that's all you have to do. they cannot deny you the right to use whatever part you want but they can refuse to pay more than what the book tells them to, so lets say the autozone motor mount was $80.00 and the H3 mount was $123.00 then you just agree to pay the $43 difference, labor is the same either way.

 

[T-rev]

Not trying to jumpin and give you more stuff to worry about but, I had that same clunk that your describing and could not track it down for a good 4 months. last week I lost my transfercase and replaced it with a used transfercase and now it is completely gone. no clunk and truck seems more responsive to acceleration.

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[14RamHemiSport]

Not trying to jumpin and give you more stuff to worry about but, I had that same clunk that your describing and could not track it down for a good 4 months. last week I lost my transfercase and replaced it with a used transfercase and now it is completely gone. no clunk and truck seems more responsive to acceleration.

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What year make and model?

 

[T-rev]

What year make and model?

2007 GMC yukon Denali 6.2l running the Borg Warner 4485 RP3

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[donjetman]

2007 GMC yukon Denali 6.2l running the Borg Warner 4485 RP3

Ours does it when transitioning from decelerating to accelerating. I've learned to make this transition smoothly to avoid the THUD/CLUNK. My guess is there's a lot of slop in the transfer case?

 

[14RamHemiSport]

Ours does it when transitioning from decelerating to accelerating. I've learned to make this transition smoothly to avoid the THUD/CLUNK. My guess is there's a lot of slop in the transfer case?

That's why I asked year make and model. My wife has an 09 Denali awd. We get a light thud once in a while when going from on the gas, letting off (say to turn) then getting back on it is when we get the thud. It's not every time though. Seems to be a concensus of drivetrain play in these trucks.

 

[wjburken]

That's why I asked year make and model. My wife has an 09 Denali awd. We get a light thud once in a while when going from on the gas, letting off (say to turn) then getting back on it is when we get the thud. It's not every time though. Seems to be a concensus of drivetrain play in these trucks.

When I experienced this with my 2007 Denali, the first time at 180K, it was a broken motor mount which was replaced. The second time I experienced the "thud", at 270K, it ended up being a combination of slack in the AWD transfer case and worn out front differential. Swapped them both out and thud went away. I think the slack in the transfer case accelerated the wear in the front differential.

 

[Rocket Man]

That's why I asked year make and model. My wife has an 09 Denali awd. We get a light thud once in a while when going from on the gas, letting off (say to turn) then getting back on it is when we get the thud. It's not every time though. Seems to be a concensus of drivetrain play in these trucks.

It’s not normal. A thud means slack or play somewhere that will only get worse over time. You should never have to be careful when hitting the gas. It’s probably time to do some diagnosing if you hear or feel a thud. Could be motor mount, differential, transfer case, transmission, u-joint etc. but whatever it is will probably cause wear on other components over time.

 

[14RamHemiSport]

It’s not normal. A thud means slack or play somewhere that will only get worse over time. You should never have to be careful when hitting the gas. It’s probably time to do some diagnosing if you hear or feel a thud. Could be motor mount, differential, transfer case, transmission, u-joint etc. but whatever it is will probably cause wear on other components over time.

I will be sure to look into it further. Sounds like we have it narrowed down to a few things at least.

 

[Koop]

Don't know if people are still answering but here was my issue:

2007 Yukon Denali XL AWD

Thud noise when accelerating from stop or thud in decrease of speed in the lower range


Once on a lift my uncle and I found that the issue was these mounts (differential):

You can also inspect the engine mounts and tranny mounts but the differential mounts were basically done and gave so much play (damn near a good inch and some change). Now I won't play when I say this was a full day project even with a mechanic whose done this for 35+ years. Once the mounts were replaced...not a single piece of noise. Shifting into drive or reverse, nothing. Accelerating, nothing... decreasing speed, nothing. Check those mounts on top of other suggestions others have given but as taught to me by a old schooler, start with your mounts and work inward. Definitely would like to hear an update on results.