Hey Hobbes, I was wonder if you've gotten this issue resolved for your X? And if so, what was the final diagnosis?

I'm experiencing very similar issues when slowing to a stop at low speed, the transmission would sometimes have that bump/jerking shake/lunging feeling. And when I have to transition from a slowing stop to accelerating, sometimes it would give a hard bump/jerking as I'm accelerating out of a turn. Recently, I got a trans fail safe error that went away after a restart (had an indy pull the code, and it showed a gear ratio fault). I'm expecting the worst (transmission rebuild or replacement), but I'm hoping to take it in somewhere for a more thorough test to determine the problem. Hoping it's something less than a full transmission, like a valve body.

I'm going to try to schedule an appointment with European Motor Works this weekend to see if they can look at my X and give it a test drive to see the symptoms.