My 2017 GMC Yukon SLT,, has been having shifting problems, including hard or delayed shifts, clunking, jerking, and even sudden jolts when downshifting.Rough or jerky shifts, particularly during acceleration and deceleration, a delay in engaging gears, especially when shifting from park to drive or reverse. Transmission shifts are very rough in slow traffic with as much as one to two-second delays in shifting into gear with a loud thump. It is so rough that it feels like someone may have ran into your back bumper. It is also bad enough that it startles the driver, and it could be a safety issue