Gmc 2014 problem

[14Grey59]

I purched my truck in december of 2014 and it now has 43000 miles on and i am starting to notice alot of problems one is that annoying flapper vale noise and the one that im really puzzled on what it is, when throttle is applied feels like my drive line jolts or is settling in and alot of hesitation i took it in and they said nothing was wrong. Looking to see if you know what it is or have the same problem. Thanks

[Brianibew]

Your driveline shudder may be the classic Chevy slip yoke problem. You'll usually notice it when coming to a stop and first accelerating from a stop. Google or YouTube it and it will explain it way better than I can, and with pictures. Hope this helped.