hungryhippo

I'm shopping for a 2016+ sierra or yukon denali. I'm a little put off by the issues I'm reading about the 8 speed. It seems like the issues may have been fixed with a redesigned torque converter. I'm not seeing many complaints about the 10 speed. I wonder how good the 8 speed is if GM/Ford had the 10 speed in development. Should I go for a 2018 Yukon with the 10 speed or go for a used model? Thanks for any input.

wu6fiend

I have the 8 speed in my 2016 Yukon Denali. I've noticed the occasional hard shift (maybe, once or twice a day, sometimes even less often than that). I've also noticed the vehicle is not especially happy under light throttle, going up a hill (it holds a higher than optimum gear longer than it should, and is not as responsive as it should be). I actually noticed this characteristic when we drove a demo Yukon XL, so this is not unique to my particular vehicle. There is also a tiny vibration/rattle noise in this circumstance (going up a slight hill, under light throttle), which I understand is some kind of valve in the exhaust. In that sense (holding an upper gear too long), it reminds me of the 700R4 in my old 1987 IROC-Z from many years ago: once it got into OD, it didn't want to shift down unless you gave it a lot of throttle). The overall driving experience of the 2016 (engine + transmission combination) was superior in my previous Yukon Denali (2009) and in fact its predecessor (2005). So in that sense, newer is not better. All that aside, though, I am very pleased with the 2016, and have no plans to change anything (some owners report disabling the AFM via a tune or Range device improves drivability). My wife, when she has driven the Yukon, has either never noticed the above, or has chosen to ignore it.

MVR 155

I have a 2015 Yukon Denali with the 8 speed...... it's much better than the 6.2L/6 speed that was in my 2008 Hummer H2. When it's cold, it will occasionally exhibit slight rougher shift characteristics. I had a 2018 Escalade rental back in February for a trip to Vail...... The 10 speed trans was absolutely seamless. Overall I'm very happy with the Denali and wouldn't have any issue suggesting the vehicle to someone else.

hungryhippo

Thank you both for the detailed responses. I am leaning towards a used yukon with the 8 speed. Apparently the 8 speed is faster than the 10 speed according to Car and Driver.

Exsanguinate

I know 4 months have passed and you probably pulled the trigger, but I would pass on the 8L90. I have a 2015 Stingray and many problems with hard shifting, not shifting, transmission shudder, and a tach fluctuating 300 rpm while cruising at steady speeds on flat surfaces.
Service writer wrote what he wanted and not what I stated the issues were. So far I've had a software update that did nothing. Next step is a new torque converter. I've already heard from people who got a new TQ and the problems we're back within several thousand miles. Rumor mill has GM releasing a brand new converter late 1st quarter of 19. Right now I don't have any faith that this will be a permanent solution, just enough of one to get you past your warranty period.
Had plans to buy a new Silverado in 2020, not anymore. Forgot to mention my son has a 2017 Sierra less than 10000 miles, same issues with his 8L90 transmission. JUNK stay away!