I had an Auburn limited slip differential and had some trouble with the positraction working properly. I discovered this problem through the troubleshooting step of inspecting the differential with the rear of the car in the air. The procedure calls for you to turn one tire and try to rotate the other tire. Since both my tires rotated independently it told me the limited slip differential was not functioning properly. After I disassembled the housing, I could see where the cone shoulders were contacting the differential housing and not the tapered portion of the housing where the cones should seat.

This is a safety lock differential stock in many 10 bolt GM applications. All of the advice I received was to replace the unit with another if it no longer could provide the traction to both wheels. The units cost anywhere from $450.00 to $800.00. This was to steep for me! Here is what I did to correct the problem and to save myself some money..

This unit has cones on either side of the spider gears in the differential housing. In my unit, I have one large spring in the center of the spider gears that provides force to the two internal cones against both left and right sides of the differential housing. What had worn were the spiral pieces of the cones and the mating surfaces of the housing where the cones engage to provide the limited slip action.

The end of the cones were bottoming out on the internal shoulder of the housing where the axle shafts slide in the splined inside diameter of the cones.The cones were not badly damaged, so I thought I'd try and get the cones to engage the housing again.

I used a lathe to machine the cone face (outer portion of cone shoulder where the axle shaft slides into it). I had a friend machine .004 to .005 on both cone shoulder ends. Once this was done, the cones shoulder did not bottom out in the housing where the axle shafts came through. They then engaged the cone housing once again.

This process cost me about 15 dollars for limited slip differential fluid, a new gasket and some elbow grease. You will, of course, have to find a friend with a lathe or take it to a machine shop. They should be able to do the job for a minimal cost.