Ah, the saga continues. Purchased a "spare" SM420 to swap out while "rebuilding" the original. My son stopped by to help me switch transmissions on the transmission jack and did a quick unrequested inspection and said 'Dad, that's got too much play on the input shaft". Upon close inspection witht the top plate off there are two or three ball bearings missing from the input shaft bearing. There are no signs of damage in or around that bearing and other than the play everythin else "looks" good. I'm thinking to replace the front bearing and needle bearings in the input shaft and moving forward with the install.....or is it time to just rebuild the one that's in it and be done with it. Darned, wanted to drive the truck next week. Thoughts anyone?