Experiencing a similar issue. I can best describe it as a hard shift between gears (guesing 2nd-3rd most of the time). Doesn't seem to happen in the higher gears. Have not detected any shudder yet but it does happen more often when the engine/car is warm rather than during the first 15-20 mn of driving.

Also, had my fluid and filter changed at the end of 2010. Wasn't experiencing these issues before this fluid and filter change.

Would appreciate any comments...