My 35D had some shudder during tight turns under power, BMW quoted $5000 or so for replacing the TC. Elsewhere in the forum I saw someone had changed the TC fluid and got reprogramming/adaptation cycle run and that fixed it. I decided to try that and luckily it worked for me too. From what i can gather the plastic gear in the actuator wears out, replacing that and changing the fluid seems to fix the issue. Her's the link to the thread.

https://xoutpost.com/bmw-sav-forums/...4bdc-4a14.html