u/Dollbaby444

When starting my 2020 and putting it from PARK to DRIVE, I'm getting a very heavy clunking sound with one pretty hard jerk of the truck. It doesn't do it every single time, but about 25%. Of course when I took it to a shop, it behaved perfectly and they didn't get to see what I'm frequently dealing with. Nothing came up on diagnostics (or so they say). Occasionally, when I'm driving, I'll get a noise with mild jerking as if it wants to shift to another gear. That's only on occasion though. Could this be in need of a new trans? If so, why wouldn't diagnostics pick up on this? How much would this run me? My warranty ended.