Clunk when accelerating after coasting at 80 km/h, and clunk when reapplying gas after coasting from 40 km/h to 60 km/h

petethepug said:

Denali
Standard or XL
2WD or 4WD

You’re mentioning km so I assume you’re up North with 4WD or AWD. Verifying will make an easier diagnosis.

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petethepug said:

Cool welcome from SoCal, deff what others have mentioned on front diff mounts / dog bone bushings. Inspect motor mounts for being popped / leaking dampening fluid, front sway bar bushing and bar attachment hard mount points.

Lube the driveshaft yoke too …

Lube Slip Yoke - AWD

Ok...so I've read, and read, searched, and searched, and I'm still not clear on the topic fully. I know that all the late model GM SUV/trucks have a slip yoke on the front of the driveshaft, and over time/miles it gets to where it doesn't slip so well and results in a bit of a drive line clunk...

www.tahoeyukonforum.com

Change out your emissions carbon canister asap. If it hasn’t released carbon pellets onto your fuel system yet, you dodged a bullet.

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kurt87 said:

Okay will do. If it did release carbon pellets into my fuel system what does that mean? Like will it hurt my engine?

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kurt87 said:

Hello,

I own a 2008 gmc yukon and am experiencing some drivetrain issues.

First of all, when I am coasting at 80 km/h and floor it my yukon makes an alarming clunk in the front end. If I accelerate not as aggressively the clunk doesn't happen.

Also, when I take my foot off the gas going 40 to 60 km/h and let the rpms drop then re-engage the gas peddle I here and feel a slight clunk. I think of it as teeth grabbing after spinning or something like that.

My yukon has 244k kms and i already changed both rear u-joints. I did the engine mount check and they seem to be absolutely fine. Engine does not move around too much at all.

I also have the following engine codes:
P0430
P0455
P1153
Should I be fixing these? Are they pressing?

Not too sure what it could be, any ideas?

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