ANTI-SPIN OVERHAUL INFORMATION

Click HERE for Anti-Spin rebuild kit ordering info

The following applies to 1967-1970 12 Bolt O axles and 1971-1975 10 Bolt O axles.

While it might be possible to rebuild your Anti-Spin carrier while it’s still in the car, we certainly wouldn’t suggest trying. The few extra minutes it takes to remove the differential carrier assembly from the housing will be time saved – and more importantly, an accurate and precise job can be performed. By taking care when removing the differential carrier (noting the main cap orientation as well as the left and right carrier shims), the carrier assembly can simply be torqued back in place. Please read all the following instructions before disassembly.

To remove the carrier assembly, remove both axle shafts by removing the axle retaining/brake backing plate nuts. Next, unbolt the four differential carrier main caps – again, be sure to note their left and right as well as top and bottom positioning. Remove the carrier from the housing (this may require some prying on the carrier). When the carrier is removed, along with it will come the carrier bearing races and differential side shims. Be prepared to catch these as it is critical that you keep these components with their respective side of the carrier.

Once the carrier is removed from the housing, it can be disassembled. Remove the pinion shaft retaining bolt and slide the pinion shaft out of the housing. Using a hammer and a punch or drift, remove the preload (“S”) spring.

With the spring removed, you can now remove the pinion gears. Rotate the side gears until the pinion gears can be removed from the housing. Note there will be thrust washers located between the pinion gears and the carrier housing. Be sure to keep the washers with their respective gears so they can be reinstalled in their same locations. Once the pinion gears have been removed, you can remove the side gears along with the clutch packs. Again, it is important that you note the location of each gear and clutch assembly so they can be reinstalled on their original side. Remove clutch packs and shims from the side gears. While the old clutches can be discarded, be sure to keep any and all shims or spacers with their respective side.

Clean and inspect all components.

If the carrier bearings show signs of wear and need to be replaced, do so now while the carrier housing is fully disassembled.

Open your 46-120 Anti-Spin clutch overhaul kit(1). Coat all clutch plates with GM SAE 80W-90 Axle Lubricant (Our part number 46-068 or available at a GM dealer). Do not use synthetic oil. Install new clutches on the side gears in the same order as the originals were removed (starting and ending with clutches with tabs). Next, install the spacer and original shims. Install one side gear and clutch/shim pack assembly into the carrier. Place both pinion gears (and shims) into carrier and install the pinion shaft. Compress the clutches, spacer and shims by wedging a screw driver between the pinion shaft and side gear as shown below.

Attach a dial indicator to the carrier so its point contacts one of the pinion gears as shown above. Rotate pinion gear – the clearance must be between .001” and .006”. If there is more than .006”, add thicker shims to the clutch/shim pack. If less than .001”, use thinner shims. This may require a combination of the original shims and the new ones included in the kit. Recheck clearance after changing shims. Remove gear/clutch pack/shim assembly and repeat the same procedure with the other gear/clutch pack/shim assembly on the other side of the carrier. After the proper clearance has been achieved on both sides, install both gear/clutch pack/shim assemblies back into the carrier. Install pinion gears by rotating the side gears. Install pinion gear thrust washers. Insert the pinion shaft into the carrier, through the thrust washer and partially into the pinion gear (this will keep the gears aligned while installing the S spring). Using a brass hammer or drift, drive the spring into position between the side gears. Next, push the pinion shaft all the way into place, install the pinion shaft bolt and torque to 15 ft. lbs. If the ring gear was removed from the carrier, we suggest using new bolts. When tightening the ring gear bolts, tighten them evenly using an alternating pattern. In four steps, bring them to a final torque reading of 85 ft. lbs.

Install carrier bearing races and side shims onto the carrier. Install carrier back into the differential housing. On 12 bolt models, torque bearing cap bolts to 65 ft. lbs. (1970 W-27 55 ft. lbs.).

Install axles – torque bolts to 45 ft lbs.

Install cover, add the bottle of GM Limited Slip Axle Lubricant Additive supplied with the 46-120 kit and fill with GM SAE 80W-90 Axle Lubricant (Our part number

46-068 or available at a GM dealer). Do not use synthetic oil.

Footnote (1) At this time, the clutches for our 46-120 Anti-Spin overhaul kit are unavailable. Due to the cost of production vs the market and demand, we do not anticipate reproducing the clutches in the near future. However, this does not mean your Anti-Spin carrier cannot be brought back to within factory specs. Under most conditions, the wear on the clutches is usually fairly minimal. Therefore, unless the clutches have been burned, there is a very good chance they can simply be shimmed to achieve the proper pinion gear to side gear backlash. After removing the carrier assembly from the housing, check the backlash as shown above before disassembling. Typically you will find they are approximately .010” out of spec. Using our Part Number 46-228 shim and spring kit, and following the same procedures as shown in this article, this kit will very likely be all that is needed to restore the effectiveness of the original Anti-Spin unit.

O Axle Spring and Shim kit (Part Number 46-228) listed HERE.

If the clutches show excessive wear or have been burned, you may need to replace the carrier assembly with one of our brand new Anti-Spin units. Click HERE for more information.

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