Unusual quick jump upon cold start

[smithscientist]

Since they replaced my transmission at 40,000 miles, I've noticed that occassionaly, but not always, there is an unusual quick half second jerk or jump feeling when I first crank the car on a cold start. It doesn't happen all the time, just some times, but it has to be a cold start when I do feel it.

Any ideas what this could be? I'm thinking maybe some bolts weren't put tight enough when they installed the new transmission?

[smithscientist]

anyone have any ideas? I spoke with the guy at the dealership and he said he would need to experience it to know for certain, but it doesn't do that strange movement/jump feeling when starting it every time. it's only like 1 out of 4 starts, and the car has to have been sitting at least 1 hour.

i never felt it until they replaced the transmission and compressor.