My transmission does a few strange things when shifting up and down. I have had quite a few low speed downshifts where it feels about like I've been rear ended. It has only happened 2 or 3 times on the road, but probably 10 times or more while I'm driving down my long driveway and right before coming to a stop. So at the end of a half mile of 10-15mph and as I either coast to a slowdown or apply the brakes before I turn into my parking space. Dealership wasn't able to replicate the issue.
The transmission also has a stall or hesitation accelerating as it enters 3rd gear, it's like a series of 3 blips that you can hear through the exhaust. My foot stays on the pedal at the same pressure, but the acceleration doesn't continue smoothly for a second or so and then picks back up and continues with the acceleration. Almost as if I am feathering the throttle. On the drive home from the dealership after they told me everything was normal, as I entered the freeway along the on-ramp I accelerated fairly aggressively and as it shifted into 3rd gear the acceleration completely fell off and the engine revved around 5k and forward momentum stalled for just a second, but at that rate of acceleration, if felt substantial. I was so pissed off.
I think they are both programming related, but my dealership doesn't seem interested in acknowledging them yet.