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One Piece Upgraded Rear Axle Kit for AMC Model 20 in 1976-1983 Jeep CJ5 and 1976-1981 CJ7, Part YCJS
The Yukon Gear YCJS one piece short axle kit replaces the factory two piece rear axle design in the AMC Model 20 differential with an upgraded one piece construction. The stock two piece axle in CJ5 and CJ7 applications is a known weak point prone to failure under off-road stress. The YCJS eliminates the center joint failure mode entirely by using 1541H alloy steel one piece axles with 29 splines, axle bearings, seals, retainers, and studs. This is a complete bolt-in kit for serious CJ rebuilds.
Features and Benefits
- Replaces factory two piece axles with stronger one piece 1541H alloy steel design
- 29 spline count for improved torque transfer and reduced stress concentration
- Kit includes two axles, axle bearings, seals, retainer plates, axle studs, and installation silicone
- Eliminates the weak center joint found on OEM two piece axles in Model 20 applications
- Fits 1973-1983 Jeep CJ5 and 1976-1981 Jeep CJ7 with AMC Model 20 rear differential
- Direct bolt-in replacement requiring no housing modification
- Prop 65 compliant warning included for California residents
- Made by Yukon Gear and Axle, the benchmark of quality for drivetrain components
Vehicle Fitment
| Year | Make | Model | Trim |
|---|---|---|---|
| 1976 | Jeep | CJ5 | Renegade |
| 1977 | Jeep | CJ5 | Renegade |
| 1978 | Jeep | CJ5 | Renegade |
| 1979 | Jeep | CJ5 | Renegade |
| 1980 | Jeep | CJ5 | Renegade |
| 1981 | Jeep | CJ5 | Renegade |
| 1982 | Jeep | CJ5 | Renegade |
| 1983 | Jeep | CJ5 | Renegade |
| 1976 | Jeep | CJ5 | Golden Eagle |
| 1977 | Jeep | CJ5 | Golden Eagle |
| 1978 | Jeep | CJ5 | Golden Eagle |
| 1979 | Jeep | CJ5 | Golden Eagle |
| 1980 | Jeep | CJ5 | Laredo |
| 1981 | Jeep | CJ5 | Laredo |
| 1982 | Jeep | CJ5 | Laredo |
| 1983 | Jeep | CJ5 | Laredo |
| 1982 | Jeep | CJ5 | Limited |
| 1983 | Jeep | CJ5 | Limited |
| 1976 | Jeep | CJ7 | Renegade |
| 1977 | Jeep | CJ7 | Renegade |
| 1978 | Jeep | CJ7 | Renegade |
| 1979 | Jeep | CJ7 | Renegade |
| 1980 | Jeep | CJ7 | Renegade |
| 1981 | Jeep | CJ7 | Renegade |
| 1976 | Jeep | CJ7 | Golden Eagle |
| 1977 | Jeep | CJ7 | Golden Eagle |
| 1978 | Jeep | CJ7 | Golden Eagle |
| 1979 | Jeep | CJ7 | Golden Eagle |
| 1980 | Jeep | CJ7 | Golden Hawk |
| 1980 | Jeep | CJ7 | Laredo |
| 1981 | Jeep | CJ7 | Laredo |
Specifications
| Specification | Detail |
|---|---|
| Part Number | YCJS |
| UPC | 883584213932 |
| Differential | AMC Model 20 |
| Spline Count | 29 spline |
| Axle Type | One piece full-float replacement |
| Short Side Length | 23.310 in. |
| Long Side Length | 26.25 in. |
| Material | 1541H Alloy Steel |
| Shipping Weight | 39.57 lb. |
| Warranty | 1 Year Manufacturer Warranty |
What's Included
- Two one piece 1541H alloy steel rear axle shafts (short side and long side)
- Axle bearings (both sides)
- Axle seals (both sides)
- Axle retainer plates
- Axle studs
- Installation silicone
Frequently Asked Questions
What is the YCJS designed to replace?
The YCJS replaces the factory two piece short axles in the AMC Model 20 rear differential found in 1976-1983 Jeep CJ5 and 1976-1981 CJ7 models with a stronger one piece design.
Why upgrade from the factory two piece axles?
The factory two piece design includes a center ball joint that is a common failure point under off-road stress. One piece axles eliminate this joint entirely, providing significantly improved strength and reliability.
Does the YCJS include bearings and seals?
Yes. The YCJS kit includes axle bearings, seals, retainer plates, axle studs, and silicone sealant for a complete installation.
Will installing the YCJS affect my vehicle warranty under the Magnuson-Moss Warranty Act?
Under the Magnuson-Moss Warranty Act, a vehicle manufacturer cannot void your warranty solely because you installed an aftermarket part unless they can prove the part caused the failure. Given the age of CJ vehicles this kit fits, factory warranty is not a concern.
What warranty does Yukon provide on the YCJS?
Yukon covers the YCJS under a one year manufacturer warranty against defects.
Are these axles a direct bolt-in replacement?
Yes. The YCJS axles install in the factory Model 20 housing without modification. Only standard hand tools and a press for bearings are required.
What is the spline count on the YCJS?
The YCJS uses 29 splines, matching and exceeding the factory specification for the Model 20 differential.
Can the YCJS be used with aftermarket lockers?
Yes. The one piece axle design is fully compatible with aftermarket locker and limited-slip units designed for the AMC Model 20 differential housing.
Installation Instructions
- Raise the rear of the vehicle and support it on jack stands.
- Remove the rear wheels and drum brake assemblies.
- Remove the rear differential cover and drain the gear oil.
- Remove the differential cross shaft retaining bolt and slide out the cross shaft.
- Push axle shafts inward to release the C-clips, then pull the factory axles out of the housing.
- Using a bearing press, remove old axle bearings and seals from the axle tubes.
- Press new bearings from the YCJS kit into the axle tubes.
- Install new seals and retainer plates.
- Apply a thin bead of the included silicone to the axle flange where specified.
- Slide the new one piece axles from the YCJS into the housing and seat them fully.
- Reinstall the cross shaft and retaining bolt.
- Install a new differential cover gasket or apply RTV; reinstall and torque cover bolts.
- Refill with the correct differential gear oil and reinstall wheels.
Prop 65 Warning: This product can expose you to chemicals including arsenic, which is known to the State of California to cause cancer and birth defects or other reproductive harm. For more information, go to www.P65Warnings.ca.gov.
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