my 2001 GC shudders (shakes) a little when I accellerate slowly from being stopped. It only seems to happen when the car shifts from first to 2nd gear, and then back in to first when I come to a stop.
80+Kms on a 3.3L...is my tranny starting to go?

Not the best of signs. I'm on my 4th caravan and this is usually the 1st indicator of something going wrong. Changing the fluid and filter may help for a little while and show you if there is metal shavings in the system. Your mileage is also "ripe" for tranny problems. Good luck!