Last week I loaned my Ranger to a friend so he could pick up a new recliner he had bought. The transmission slips at times when shifting from first to second, but no real problem. About 45 minutes later my friend called to say the transmission went out on the freeway. When I got there, the bottom of the truck was covered with transmission fluid and nothing showed on the dipstick. I had it towed home. The next day I added fluid and the truck drove fine around the neighborhood and there was no fluid leakage but the fluid smells burned. Does anyone know the likely cause, where the fluid leaked from and how I fix it?