Just for reference I don't own and or ever worked on your series of tractor/ 55. I only want to help clarify what beenthere has documented. Your front axle asmy has what could be called and intermediate gear box. It is probably there for packaging reasons/ getting the front drive shaft closer to the car body/ increased ground clearance to the front drive shaft/ or alignment with the transmission and or any of a dozen other reasons. Looking at the parts catalog I cannot tell if it is a one to one gear box and or some type of reduction gear box. With that being said when checking the backlash as shown in your video you are also picking up the backlash of the intermediate gear box, aka the two gears and their splined connections, along with the ring and pinion backlash. That backlash value is not listed in the maintenance instructions. To check the ring and pinion backlash you would need to disassemble the front axle assembly as shown in the maintenance instructions. A lot of work. Or you could do a simplified check just for excessive ring and pinion backlash by removing this intermediate gear box. You then would reverse the back lash check by rotating the pinion shaft. This would eliminate backlash in the intermediate gear box. This alternate check has it own problems. You cannot verify without major teardown if the ring gear is moving during the backlash check. You would only want to very lightly rotate with your fingers the pinion shaft. This assumes that you cannot rotate the ring gear due to its mass and connections using light finger pressure. If you wanted to get a backlash value you would need to clamp something like a flat bar to the pinion shaft. and check the end play at the radius value of the ring gear. From looking at the video and looking at the design I would speculate that the majority of the end play is in intermediate gear box and not the ring and pinion. The intermediate gear box may act like a slip clutch on a brush hog. It loads up and wears more that the ring and pinion thus protecting the ring and pinion. That's just a guess. Hope this helps. Later.
