VW 91 Passat Wagon has trouble shifting through gears when cold?

Currently 185k miles, 1st tranny replaced at 80k. The car starts jerking when shifting gears and sometimes completely drops out of gear and won't let me accelerate at all. There is transmission fluid in it. Funny thing is when it is very low on oil (oil leak) it shifts fine and when it is really warmed up it works fine. Any experience with this?VW 91 Passat Wagon has trouble shifting through gears when cold?I see something wrong, Automatic right? do you check the fluid with the engine running (Warm is best)? Check engine oil "engine off", transmission with "engine running", warm if possible. What colour is the fluid (Red or Reddish "good", brownish or dark "Bad")? 105,000 time for change, flush, %26amp; check-up!