Since my truck was first delivered, its had the weirdest problem. It only happens when its cold out (i.e. below freezing), and I use the factory optioned/installed remote starter system. If I start the truck via remote start, let it warm, then hop in and put my key in, the first shift from P into either drive or reverse is extremely harsh/abrupt/forceful. The colder it is the worse the shift is. On a truly cold morning, it feels like another car rear ended you when you make the shift. I'd venture to guess the trans makes this shift with maximum line pressure applied, as if it thinks its under load.
Oddly, if you immediately return to Park and attempt Drive or Reverse again, its smooth as butter. Also if you don't use the remote start there is no issue, and if its warm out and you remote start theres no issue.
I've had the truck into two dealers on 3 separate occasions, and each time they state they can't duplicate the problem. It's very difficult/frustrating trying to time a cold day, and have the diagnosing tech use the remote start when they go to drive it.
Thought I'd try the forum in case anyone has had a similar issue or has any opinion on what could be causing this? I can't fathom what ambient temperature, remote starter, and transmission control could possibly have in common? Thanks.

 

had to go back and search from my post from March 2015:


Same issue on my 2011 EB RWD

Have had a TSB flash performed a year or so back for hard shifting and seemed to improve
still did it sporadically, especially on cold start. would do it at low speed in parking lot on cold start. would do it every now and then on freeway when pushing gas to pass and had to downshift.
would do it when in tow mode pulling a trailer and pressing brake which cause trans to downshift.

figured it just needed another flash


Just got my truck back from the dealer yesterday after a week in

Tech notes:

"Performed elect trans diag codes present. Inspected maincontrol found binding regulator valve, replace valvebody, after road test trans still shifting harsh 1-2. necessary to r and r trans. Found worn and twisted intermediate piston seal causing harsh 1-2 shift. Place trans on bench, overhauled trans. Recond. all drums, inspected converter, flush cooler lines after road test trans shifts normal."

Caught this at 45,500 and warranty expires at 48k
this repair cost them $1,974


Good thing is it does feel like it shifts better but I was never able to reproduce the issue on command so I wont know unless it just happens. Bad thing is its back at the dealer for a CEL. They messed with it before leaving and supposedly it was a loose connector on O2 but it came back on as soon as I restarted it so I had to bring it back since it was after 6 and their techs had just left.

 

I'm at ~83k and haven't had the problem since the rebuild

 

I have a 2018 2.7 RWD and have experienced the same behavior without using remote start. My garage doesn’t get below 40 and the hard engagement from P to D only occurs once in the morning. Like the OP, I can shift from P to R and D after that and it’s butter.