Overview
The Crown Automotive J8120325 is a Trac Lok differential disc kit for the AMC Model 20 rear axle. The Trac Lok is a clutch-type limited slip differential, and the disc kit is the set of clutch discs that limits wheel slip between the two axle shafts. It is a direct fit in the rear position.
It fits 1976 to 1983 Jeep CJ5, 1976 to 1986 CJ7, 1976 to 1986 J10 and 1981 to 1985 Scrambler models in the years and trims covered. It does not fit Cherokee, Wrangler or later models.
Key features
- Trac Lok differential disc kit for the AMC Model 20
- Rear position, direct fit
- Clutch discs that limit wheel slip between the axle shafts
- Part number J8120325
Clutch wear and when to replace
Trac Lok clutch packs wear with use. Limited slip action depends on the discs gripping the case and side gears, so a pack that has glazed or worn thin lets the wheels slip more freely than intended. On a trail rig, the first sign is often a wheel that spins on one side under light throttle, or chatter when turning slowly with load on the axle.
Because the discs and case work together, many rebuilders replace the friction discs at the same time as the pinion and carrier bearings whenever the carrier is out. Clean the case thoroughly, check the side gears for scoring, and make sure the discs sit flat before the cover goes back on. Use a gear oil labeled for limited slip differentials, since standard fluid can cause chatter.
- Inspect friction discs for glazing or uneven wear
- Check side gears and spider gears for scoring
- Replace worn bearings during the same teardown
- Confirm preload before final assembly
Specifications
| Brand | Crown Automotive |
|---|---|
| Part number | J8120325 |
| UPC | 848399066746 |
| Differential | AMC Model 20, Trac Lok |
| Part type | Differential disc kit |
| Position | Rear |
| Fitment | Direct fit |
Vehicle fitment
It fits the 1976-1983 Jeep CJ5 in Base, Golden Eagle, Laredo, Limited and Renegade versions, and the 1976-1986 Jeep CJ7 in Base, Golden Eagle, Golden Hawk, Laredo, Limited and Renegade versions. It also fits the 1976-1986 Jeep J10 Base and the 1981-1985 Jeep Scrambler.
It does not cover Cherokee, Wrangler or later models. Confirm fit for your vehicle’s year, model and trim before ordering.
Installation notes
A Trac Lok disc kit has to be set up with the correct clutch preload and matched to the differential case. Check the clutch discs for wear and set the preload before the carrier goes back in, since the kit controls how much slip the axle allows.
What’s included
One Trac Lok differential disc kit for the AMC Model 20 rear axle.
