My 380 shifts OK when hot but allows the engine to rev up between 1- 2 and also between 2-3 when cold but in 1 to 2 seconds goes on and shifts. The local mechanics have adjusted numerous times and flushed it out 3 times with varying temporary results but in the end it is back to the same. Does anyone have an inexpensive solution or do I have to try to find another transmission or is it feasible to overhaul?