Yukon GM & Chrysler 11.5" Grizzly Locker - 38-Spline
YGLGM11.5-38
The Yukon GM & Chrysler 11.5" 38-Spline Grizzly Locker is a heavy-duty automatic locking differential built for GM and Chrysler 11.5" rear axle assemblies upgraded to 38-spline axle shafts. Whether you're building a high-torque Duramax or Cummins truck, a heavy-duty tow rig, or a full-size off-road vehicle, the Grizzly mechanically locks both axle shafts together under power to help maintain traction when one tire loses grip. It's a strong drivetrain upgrade for builds that need more traction than an open differential without permanently locking both wheels together like a full spool.
Built with heat-treated 8620 steel internal components and Yukon's patented mechanical locking design, the Grizzly uses large engagement teeth to handle the shock loads created by high torque, heavy vehicles, and demanding terrain. The automatic locking mechanism allows differential action during turns when operating conditions permit, without requiring an air compressor, wiring, or driver-operated switches. Designed for compatible GM and Chrysler 11.5" axle assemblies, this 38-spline configuration requires upgraded axle shafts and machining of the factory spindles to provide the necessary shaft clearance.
Includes:
- (1) Yukon GM & Chrysler 11.5" Grizzly Locker - 38-Spline
- Fully Assembled Internal Locking Mechanism
- Locking Differential Assembly
Important: This locker requires 38-spline axle shafts and modification of the factory axle spindles. Factory spindles must be bored to accept the larger 38-spline axle shafts. Yukon tool YT H32 is required for the spindle modification. Axle shafts, machining tools, and additional installation components are not listed as included.
Specifications
| Manufacturer | Yukon Gear & Axle |
|---|---|
| Product Type | Automatic Mechanical Locking Differential |
| Axle Platform | GM / Chrysler 11.5" |
| Ring Gear Diameter | 11.50" |
| Axle Spline Count | 38-Spline |
| Differential Type | Automatic Locker |
| Locking Style | Mechanical / Automatic Engagement |
| Internal Material | Heat-Treated 8620 Steel |
| Engagement Design | Patented Heavy-Duty Locking Teeth |
| Traction Type | Full Mechanical Lockup Under Load |
| Differential Cover Bolt Count | 14 |
| Axle Position | Rear |
| Axle Shaft Requirements | 38-Spline Aftermarket Axle Shafts |
| Spindle Modification | Required - Factory Spindles Must Be Bored |
| Required Machining Tool | Yukon YT H32 |
| Air Compressor Required | No |
| Electrical Controls Required | No |
| Assembly | Assembled in the USA |
| Installation Type | 38-Spline Axle Conversion & Differential Locker Installation |
| Primary Application | Heavy-Duty Diesel Trucks, Towing & High-Torque Off-Road Builds |
| Quantity | Sold Individually |
Fitment
Designed for compatible GM and Chrysler 11.5" rear axle assemblies upgraded to 38-spline axle shafts. The vehicle applications below are reference platforms only. Verify the installed axle and conversion requirements before ordering.
| Make | Model | Year Range | Axle Application |
|---|---|---|---|
| Chevrolet | Silverado 2500 | 2001–2004 | GM 11.5" Rear, 38-Spline Conversion |
| Chevrolet | Silverado 2500 HD | 2001–2015 | GM 11.5" Rear, 38-Spline Conversion |
| Chevrolet | Silverado 3500 | 2001–2006 | GM 11.5" Rear, 38-Spline Conversion |
| Chevrolet | Silverado 3500 Classic | 2007 | GM 11.5" Rear, 38-Spline Conversion |
| Chevrolet | Silverado 3500 HD | 2007–2015 | GM 11.5" Rear, 38-Spline Conversion |
| Dodge | Ram 2500 | 2003–2010 | Chrysler 11.5" Rear, 38-Spline Conversion |
| Dodge | Ram 2500 Van | 2003 | Chrysler 11.5" Rear, Verify Axle |
| Dodge | Ram 3500 | 2003–2010 | Chrysler 11.5" Rear, 38-Spline Conversion |
| GMC | Sierra 2500 | 2001–2004 | GM 11.5" Rear, 38-Spline Conversion |
| GMC | Sierra 2500 HD | 2001–2015 | GM 11.5" Rear, 38-Spline Conversion |
| GMC | Sierra 2500 HD Classic | 2007 | GM 11.5" Rear, 38-Spline Conversion |
| GMC | Sierra 3500 | 2001–2006 | GM 11.5" Rear, 38-Spline Conversion |
| GMC | Sierra 3500 Classic | 2007 | GM 11.5" Rear, 38-Spline Conversion |
| GMC | Sierra 3500 HD | 2007–2015 | GM 11.5" Rear, 38-Spline Conversion |
| Ram | 3500 | 2014–2015 | Chrysler 11.5" Rear, 38-Spline Conversion |
Fitment Notes:
- Fits compatible GM and Chrysler 11.5" rear axle assemblies
- Requires 38-spline aftermarket axle shafts
- Not a direct replacement for factory axle shafts with different spline counts
- Factory spindles must be bored to accept the larger axle shafts
- Yukon spindle boring tool YT H32 is required for the specified modification
- Verify axle identification, differential configuration, and spline count before ordering
- Professional machining and differential installation are recommended
- Vehicle applications are reference fitments; factory axle equipment may vary
Installation Warning: This 38-spline locker requires a properly completed axle shaft conversion. The factory spindle bore must provide sufficient clearance for the upgraded axle shafts. Do not attempt installation without verifying the required spindle machining, axle shaft dimensions, and differential compatibility.
FAQ
What does the Yukon 11.5" Grizzly Locker do?
The Grizzly Locker automatically locks both axle shafts together under power, helping deliver traction to both rear wheels when one tire loses grip. It's designed for heavy-duty trucks and off-road builds that need more traction than an open differential without permanently locking both wheels together like a full spool.
Will this locker fit my factory Duramax or Cummins rear axle?
It is designed for compatible GM and Chrysler 11.5" rear axles, but the 38-spline configuration requires upgraded axle shafts and spindle modification. It is not a direct bolt-in replacement for a factory axle with a different spline count. Verify the axle and conversion requirements before ordering.
Why do the factory spindles need to be bored?
The upgraded 38-spline axle shafts require additional clearance through the factory spindle bore. The spindle must be machined to the correct dimensions before the larger shafts can be installed. Proper machining is important for axle shaft clearance, alignment, and long-term drivetrain reliability.
What is Yukon tool YT H32 used for?
YT H32 is the specified tool for boring the factory axle spindles to accommodate the upgraded 38-spline axle shafts. It is required for the spindle modification described in this application and is not listed as included with the locker.
Does this Grizzly Locker require an air compressor or wiring?
No. The Grizzly is a fully mechanical automatic locker. It engages under drivetrain load without an air compressor, electrical wiring, switches, or driver-operated controls.
How is a Grizzly Locker different from a full spool?
A full spool permanently locks both axle shafts together and forces both wheels to rotate at the same speed. The Grizzly Locker locks under load but can allow differential action during turns when operating conditions permit. This makes it more suitable for vehicles that need traction while retaining some differential action.
Can this locker be used in a street-driven truck?
Automatic lockers can be used in some street-driven applications, but drivers should expect changes in handling compared with an open or limited-slip differential. Engagement and disengagement may be noticeable during turns, throttle changes, and parking maneuvers. Consider the vehicle's intended use and follow Yukon's application recommendations.
Does the locker include upgraded 38-spline axle shafts?
No. This listing includes the Grizzly Locker assembly only. The 38-spline axle shafts, spindle machining tool, and other conversion components are not listed as included and must be sourced separately.
Is this locker a good choice for high-horsepower diesel trucks?
Yes, when matched to the correct axle and drivetrain configuration. The Grizzly's heavy-duty mechanical design and 8620 steel internals are intended to handle demanding torque and traction loads. Overall reliability still depends on the axle shafts, gearing, housing condition, machining quality, and proper differential setup.