We are rebuilding a IH 1206 tractor. The rear axle ring gear seems perfect but the pinion gear has a number of teeth with erosions in the middle but with perfect metal at the edges. One possible cause is that the lubricant had water in it. It is likely that we can run with this rear axle for a decent time or is it necessary to fix. Also looking a an exploded parts diagram the pinion seems not to have its own drive shaft attached but rather seems to slip over a splined shaft. This raises the possibilty of replacing only the pinion rather than a matched rind-pinion set. Also it might be possible to replace the pinion more easily than by a total tear down. Please advise
Toys - Farmall - IH Tractor 706, 756, 806, 856, 1206, ITIH32
Answers & Comments
I don't have a diagram for you but likely you can use both ring and pinion gears "as is" . The cause of the pitting really does not matter as long as the case is clean and free of any metal debris.(providing the gears have no stress cracks). Never replace a ring or pinion gear alone. they are matched sets and therefore will quickly wear and fail even with the best "setup" procedures. A tractor rear is pretty much a low speed application and should last a very long time unless abused or used with incorrect lube.