Originally Posted by BarryB

Actually its not the input shaft that is the problem. its the drum that the input shaft goes into. On a stock transmission The drum has splines which are aluminum and that is where they strip out. How do I know this I went to a reputable transmission shop here locally. He showed those pieces he removed from his personal rig. He told me he had 70,000 on that rebuild before they broke. He pulls some heavy trailers with his. 28 ft box race car trailer, and a 35 ft fifth wheel camper. Its is nice to have reputable shops in your area that will show you what and why things need to be done before they just tell you and charge an astronomical price to build your trans.