Ford 601-641-801 Tractor 4 Speed Transmission Rear Differential & Pinion. Good used Ford 601-641-801 Tractor 4 Speed Transmission Rear Differential & Pinion. All teeth are good. I always try to do my best to make sure that my customers are satisfied. I sell used parts, they are USED. I try to describe them the best that I can, but I do miss things. _gsrx_vers_468 GS 6.4 (468).