Driving to work on the freeway in my 83 300sd I heard this loud grinding noise coming from the trans. I made it to the side of the road, 1/4 miles before the baybridge toll plaza. The trans had no forward or reverse. Caltrans was nice enough to tow it to the shop where I work as a mechanic. What I found was the nut that holds the flange to the output shaft of the trans came off. This caused the flange to disconnect from the out output shaft at 70 mph. The splines of the flange got ground away by the spinning output shaft. No big deal to change the flange, I have a spare. The problem is the the threads of the output shaft are pretty cewed up too. Is it possible to replace the output shaft on the trans with the trans still in car thanks Steve