Built for heavy-duty GM and Chrysler 11.5" axle builds, this 38-spline Grizzly Locker is designed for trucks and rigs that demand maximum traction and durability. Whether you're running a Duramax or Cummins tow rig, a high-horsepower street truck, or a full-size off-road build, this locker delivers true mechanical lockupsending 100% of available torque to both wheels under load.

Engineered to handle extreme torque and shock loads, this locker features a patented internal design with larger engagement teeth and 8620 steel internals for increased strength and longevity. It automatically unlocks during turns for improved drivability while maintaining full traction when needed. Assembled in the USA.

Includes:

• (1) Mechanical locking differential (38-spline)
• Fully assembled internal gear set
• Installation-ready unit for GM and Chrysler 11.5" axles

Specifications

• Fits GM and Chrysler 11.5" rear axles
• 38-spline axle compatibility
• Automatic mechanical locking differential
• 100% torque transfer under load
• 8620 steel internal components
• Patented gear design for increased strength
• Assembled in the USA
• Differential Cover Bolts: 14

Fitment

• Requires tool part number YT H32 for spindle modification
  
• Factory spindles must be bored to accept 38 spline axles

Tech Insight

The 11.5" axle platform is built for high-load applications, but factory differentials can struggle when torque and traction demands increase. A mechanical locker like the Grizzly ensures both wheels receive equal power, improving traction in towing, off-road, and performance scenarios.

Upgrading to 38-spline axles significantly increases axle strength, but requires proper spindle modification for fitment. Ensuring correct machining and installation is critical to maintaining reliability in heavy-duty builds.