Originally Posted by
zipperfoot
I thought the reason for sanding diff rings was to not only insure they are flat, but to promote the diff balls rolling on the rings as opposed to them sliding across the rings which we all know will cause flat spots on the balls.
I have come to believe a stock diff can be just as smooth and last just as long as any after market kit. It all depends on how well it was built, and taking the time breaking it in properly. I learned that lesson after rebuilding my 22 diff about 22 times.
22 times good one LOL. A stock diff has scuffs and pours. A sanded diff correctly sanded in a figure 8 motion will work pretty good for a short time. But it will be more porous and thinner.
If you polish them to the point of being a glass or mirror finish you will get slippage. But it can be done if you break it in right. But you sacrifice making the surface less flat and making it thinner. Polishing is good lightly to make the ring debris free after sanding them. Cleaning is good enough but there will be more pours with a fine metal dust. I have had sanded diffs with thick gunky black grease after running them from not cleaning them good enough before building them. I have always used 800 grit, could be that reason? Most fellas use 600 to my knowledge.