Message: "96 Dakota 3.9L club. 300 miles into Mexico and I blow a tranny cooler line. Patch it up but all they have is Dexron II. Runs OK, get home, drain fluid and put in Plus 3. Three weeks later, tranny makes weird whirring sound in OD. If I pop it into neutral or turn off the OD switch, it stops. What have I done, and how can I fix it?