davidegl

It clunks sometimes on deceleration when shifting up if that is understandable. IE You are accelerating and let up on the gas, trans shifts up and clunk happens. Not always and depends on speed...seems to be in the 20-30 mph area mostly.

Your idea of "normal" is based on your experiences as is mine. I'm guessing, without any way of knowing, that the clunk you experience in the two vehicles you mentioned are not comparable to the issue in my truck. The three other GM trucks I had with significant issues didn't have this specific problem. The 2008 Tundra with 90,000 miles I traded in on this Denali didn't have any "clunk" at all. A loaner truck from the dealer that I drove for two days didn't have this issue. A friend of mine with a 2002 GM half-ton and over 270,000 miles has zero "clunk". I'm quite sure you would agree it as a serious quality defect if you experienced the same degree of issue. Anyway, to each his own. When I buy a $60m vehicle, regardless of who the manufacturer is, I expect it to be a quality product. This truck is the antithesis of a "quality product."

Same problem on my 2015 Denali. Dealer has looked at it three times and service advisor has heard the loud "clunks". The dealer says it won't affect longevity and at 22m miles I can't refute that. Even if it doesn't affect longevity, it will definitely have a detrimental effect on resale. I emailed GM corporate and received three phone calls from a lady who was asking about my progress. I told her there was none. You may know by now that GM has issued a TSB telling dealers not to fix the problem and they will not be reimbursed if they do. I'm currently looking for a quality driveline service facility in the midwest hoping I can get it fixed. I have had five GM trucks and really only two without significant issues. Those who are thinking I should have learned my lesson before now have a valid point. Never again is all I can say.

I'm probably missing something obvious but what benefit should I expect to gain by not referring to the clunking noise with my dealer?

Just for reference...I have the eight speed. I will find it hard to accept living with that defect on any new truck. Maybe my dealer will be more accommodating.

I have a 2015 sierra denali with the "clunk". About 1400 miles and the first I noticed it was about 200 miles. It occurs when shifting up or down at low speed with little throttle. Feels/sounds very much like u-joint but hope it isn't the differential. Haven't had to dealer yet. Has anyone solved this issue either on their own or with dealer assistance?