randeez
Full Access Member
Like a potato.
What did you do to your NNBS GMT900 Tahoe/Yukon Today?
- Thread starter phattyford
- Start date
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mobil 1 oil change and tire rotation at the stealer cause I have to keep my warranty savvy, and I got underneath and did my monthly visual inspection for leaks and stuff, check all the usual suspects bushings, end links, etc. she's looking good, but still bewildered by the "clunk" im getting on a hard acceleration, it's not the motor mounts we just checked them while I was in the service drive, only real suspect is the slip yoke but it only clunks on a hard acceleration from stopped or already moving.
iamdub
Full Access Member
Could be a blown shock. Go circle the mall to test it out on the speed bumps. See if you can replicate the sound without goosing the pedal. You wanna see if a sudden uptravel in the front or downtravel in the rear makes the noise.
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has done it since since day one when i bought it a year ago, doesn't clunk on speed bumps or going in or out of the driveway, turning hard, nada....., I have replaced the front shocks, rear shocks, sway bars are upgraded to hellwig, new engine and at least 2 new motor mounts, and both front & rear differentials were rebuilt less than 5k ago, still clunks......ON HARD ACCELERATION and it feels and sounds like it is coming from the engine compartment but the motor mounts check out, I'm thinking maybe a transmission mount? I don't know, it did it today when I was already going 70 and went to pass, clunk......(afm is disabled).I'm taking it in to do a test drive with a tech on Monday or maybe one day this week if I get the time, gotta get it narrowed down my power train warranty expires in about 800miles.
iamdub
Full Access Member
Transmission mount? Is it AWD?
Yes it is awd 2012 Yukon xl denali, it's really strange because I am pretty good at figuring things out and the dealer attributed it to the rear differential, but yet after putting a brand new g80 in it low and behold, still the same problem.
PG01
Supporting Member
Gotta be ds, u greezed it lately? We talked about this already, no?
swathdiver
Full Access Member
Did they change the ring and pinion gears and the differential's yoke when they changed the G80? Have you pulled the driveshaft and greased the splines in the slip yoke? Dry yokes clunk like that, as do bad u-joints.
They did the pinion bearing, pinion seal, side bearings, g80, and the front diff was rebuilt with new bearings, seals, spacer, gaskets, etc. say's they set pinion dept backlash and preload, doesn't say anything about the yoke anywhere, but it is my understanding that the yoke would make a clunk pretty much anytime? including when braking, but mine does not
Took it in this morning to test drive with a tech and of course after 15 minutes of trying to MAKE it clunk it didn't do it, it kind of did it a smidge like 2 times, so I left it and asked them to just double check the differential/driveline, etc, had them lube up the slip-yoke, picked it up at the end of the day, so ill see if that was the issue or not over the next couple days, they said everything checks good, so maybe it's just my heavy foot when everything is lined up and it clunks? I don't know....still love it though 
