I posted this in another thread the other day when someone asked a similar question...
Welcome to the forum. I'll give you my advice, based on several months of research here and on other forums, as well as my own experience in these vehicles. I do not own one, so my impressions of their road manners are based on two or three extensive test drives. I'm also not a
GM fanboy, or Ford or
Dodge.....I've owned pickups and suvs of varying models covering all three brands.
There are numerous issues to look out for when purchasing one new or used:
The buffeting, vibration and pressure issues are occurring over both short and long wheelbase models. At first I believed most problems were in conjunction with 22" oem wheels, but I've seen other info here and elsewhere that proves the issues aren't specific to that. The cabin on these things are so airtight, coupled with the thin sheet metal, roof rail issues and crappy factory
tires....it creates the sensation of being inside a base drum in extreme cases (with the buffeting and pressure). Changing to nice Michelins has helped some people, some it has done little or nothing for them. Updated body mounts were hopeful for 2017, and I've read those aren't working out to be a fix either. I've also seen extensive posts about AC failures, which supports some owner data on 2015/2016 models I found on a consumer reports type site. Some of the GMC folks are more knowledgeable than I in regards to any 8sp tranny issues, so I can't comment much on that. The tranny on the 5.3's is quirky, but seems to be greatly improved by disabling the active fuel management that shuts the engine down to 4cyl when the vehicle computer determines its "ok" to do so.
If I were to decide to purchase one, I'd get the 3.42 rear end. I've not driven one with the 3.08 but the 3.42 to me seems like a good match for either wheelbase, I wouldn't want it to have any less acceleration off of a dead stop than it already does and 3.08 would certainly be a difference. I am not familiar with whether or not there are different rear end gear options for the 6.2/8sp, the gear ratios I referenced here are for the 5.3/6sp.
The only other bit of advice I'd offer.....people here and elsewhere will tell you to go and test drive several yukons in the trim and configuration you want until you find one that doesn't display any of the problems above. I'm not knocking them or that advice in any way, I understand the reasoning behind it. But a vehicle that I should drive multiple examples of in order to find a "good" one......odds aren't in my favor that particular vehicle purchase is going to end up being a pleasant ownership experience. So, maybe I shouldn't be thinking of buying a truck that I need to go out and
drive x number of them before I find one that doesn't seem to have problems already....on a brand new truck mind you. That's where I am with the idea of one of these. As much as I like the interior and exterior styling, I'm not sure yet that I want to gamble on the possibility for the hassles and irritation of the problems. Been there and done that.