2014 Yukon XL Denali Knocking Noise

[booboo23]

Hello all. I somewhat recently purchased a 2014 Yukon XL Denali with 140K miles. I just started noticing what I will call a knocking noise (that you can feel... like going over a small pot hole) when the car is at a stop and I press the accelerator relative quickly. The problem doesn't exist if I slowly get up to speed, nor does it exist when accelerating quickly between gears. My initial hunch is u-joint, but am no expert. Anyone have any ideas?

Thanks!

 

[swathdiver]

Hello all. I somewhat recently purchased a 2014 Yukon XL Denali with 140K miles. I just started noticing what I will call a knocking noise (that you can feel... like going over a small pot hole) when the car is at a stop and I press the accelerator relative quickly. The problem doesn't exist if I slowly get up to speed, nor does it exist when accelerating quickly between gears. My initial hunch is u-joint, but am no expert. Anyone have any ideas?

Thanks!

It's probably your driver's side engine mount.

 

[booboo23]

Even though I feel the the bump somewhere in the rear?

 

[gooffeyguy]

While stopped in drive and holding the brake, blip the gas and see if you hear/feel it. If you can pop the hood and watch, or have someone watch the engine while blipping the gas and see how much the drivers side of the engine rises.

 

[swathdiver]

Even though I feel the the bump somewhere in the rear?

Well, if it's back there I would be checking the pinion and u-joints.

 

[Joseph Garcia]

Check your front differential mounts and bushings. I had that clunk, until the 2 differential mounts and bushings were replaced. Clunk gone.

 

[iamdub]

Even though I feel the the bump somewhere in the rear?

I swore mine was coming from the rear. I guess the bump travels through the frame and into the seat mounts.

In an open area in case it launches, open the hood, hold the brake hard and jab the throttle sharply to a little under halfway. Watch the engine through the gap where the back of the hood meets the cowl. If the bumping coincides with the engine movement, get you some mounts. I'd recommend the GMT800 "Hummer H3" mount, and that you replace both sides and the transmission tail mount.