Bought a very used L3410 about 2 months ago. Noticed the 4WD slipping and disengaging. Replaced the couplings on the shaft from rear to front. When I pulled the front coupling off, this is what I found. The teeth on this front shaft are almost non-existent. (This is the front, looking up from the bottom of the tractor, where the front coupling would fit.) What am I looking at as far as repairing this? If I pull this cover off, can this “gear and shaft” be replaced? Or is it more extensive than that. Thanks for the help!