I reacently filled my truck with a lot of weight in the bed. I have ben having leaking problem in the rear differential and becasue of this leak and weight. I over heated the rear differential and ran it dry on a road trip. I let my truck cool and filled the rear diff. with new fluid, but as I continued to try and drive their has been a noise that does not sound good, as well as I can feel that something is very wrong with it. I decided to get it towed due to this problem.The truck is a 1992 toyota pickup and is only rear wheel drive. Any advice on repair and cost would be greatly appriciated.