I have 200k on my 2015 Yukon xl denali. It has a 6.2 liter with 8 psd transmission. At 175k I had all the lifters replaced due to a collapsed lifter. About a 2 month ago noticed a clicking on exceleration, but would go away after a few seconds. Then started to turn up more and more. Only hear it when exceleration. If the truck is in park it will not do it!! I have taken it to mechanics and they can't figure out what's going on. Any advice would be great, thanks David Murr