Yukon Gear Master Overhaul Kit for GM 12-Bolt Truck Differential

Yukon Gear YK GM12T Master Overhaul Kit for GM 12-Bolt Truck Differential

The YK GM12T is a complete rebuild kit engineered for the General Motors 12-bolt truck rear differential, one of the most capable and sought-after axles ever installed under American trucks and SUVs. Whether you are restoring a classic Chevrolet or GMC work truck or rebuilding a heavily used axle from decades of service, the YK GM12T includes every component needed for a professional-grade overhaul. Yukon Gear designed the YK GM12T complete rebuild kit around premium Timken bearings and precision shims so the finished assembly delivers the reliability these legendary differentials are known for.

Features and Benefits

• Premium Timken carrier bearings and pinion bearings rated for high-torque truck applications
• Precision ground shim sets for accurate pinion depth and carrier preload adjustment
• OEM-quality pinion seal and axle seals to prevent gear oil leaks
• Ring gear bolts, pinion nut, and crush sleeve included for a complete hardware refresh
• Gear marking compound and brush included to verify ring-and-pinion contact pattern during setup
• Thread-locking compound for ring gear bolt installation
• Differential cover gasket included for a clean, leak-free reinstall
• Covers the GM 12-bolt truck axle (distinct from the 12-bolt passenger car application)
• All components packaged and quality-controlled by Yukon Gear

Fitment

Specifications

What's Included

• Timken carrier bearings with races (2 sets)
• Timken pinion bearings with races (front and rear)
• Pinion seal
• Axle seals (pair)
• Complete pinion depth shim set
• Complete carrier shim set
• Ring gear bolts
• Pinion nut
• Crush sleeve
• Thread-locking compound
• Gear marking compound with brush
• Differential cover gasket

Frequently Asked Questions

Q: What is the difference between the YK GM12T and YK GM12P?
A: The YK GM12T is for the GM 12-bolt truck rear axle found in Chevrolet and GMC light-duty trucks and SUVs. The YK GM12P is for the GM 12-bolt passenger car axle used in Chevelle, Camaro, Nova, and other A-body and F-body vehicles. Confirm your axle type before ordering.

Q: What years of Chevrolet trucks does the YK GM12T fit?
A: The YK GM12T complete rebuild kit covers 1965 through approximately 1987 Chevrolet and GMC trucks and SUVs equipped with the GM 12-bolt truck rear differential.

Q: Does this kit include Timken bearings?
A: Yes. The YK GM12T includes genuine Timken carrier bearings, pinion bearings, and all bearing races.

Q: Will installing this kit void my vehicle warranty?
A: Under the Magnuson-Moss Warranty Act, a manufacturer cannot void your warranty solely because an aftermarket part was used. Coverage can be denied only if the aftermarket part directly caused the failure.

Q: Is a crush sleeve included?
A: Yes. The YK GM12T includes a new crush sleeve, pinion nut, and ring gear bolts for a full hardware refresh.

Q: Do I need special tools for installation?
A: Yes. A bearing press, dial indicator, inch-pound torque wrench, and depth micrometer are needed to set pinion depth and preload correctly.

Q: Is gear marking compound included?
A: Yes. The YK GM12T includes gear marking compound with a brush for verifying ring-and-pinion contact pattern.

Q: Is a differential cover gasket included?
A: Yes. A differential cover gasket is included in the YK GM12T complete rebuild kit for a clean reinstall.

Installation Instructions

1. Drain the differential gear oil and remove the rear axle shafts per your service manual.
2. Remove the differential cover and thoroughly clean both mating surfaces.
3. Remove the carrier assembly and inspect the housing bore for wear or damage.
4. Extract the pinion shaft and note the original shim stack thickness for reference.
5. Press off the old pinion bearings and install the new Timken pinion bearings from the YK GM12T kit.
6. Use the included shim set to establish correct pinion depth; verify with a dial indicator.
7. Press new carrier bearings and races onto the carrier assembly.
8. Install the carrier, set backlash to GM specification, and verify contact pattern using the included marking compound.
9. Apply included thread-locking compound to ring gear bolts and torque to specification.
10. Install the new pinion seal and torque the pinion nut to achieve correct pinion bearing preload.
11. Install new axle seals, reinstall axle shafts, and torque all fasteners to specification.
12. Install the cover with the new gasket and fill with the appropriate gear oil type and quantity.
13. Road test the vehicle and inspect for leaks after the initial break-in period.

California Proposition 65 Warning: This product can expose you to chemicals including lead and lead compounds, which are known to the State of California to cause cancer, birth defects, and other reproductive harm. For more information, visit www.p65warnings.ca.gov.