Differential Repair, Re-Gearing & Locker Installation in Corona, CA

UNITRAX by JBM Offroad — Serving Southern California for over 37 years.

Come see the pros in Corona, California, where we specialize in differential repair, ring & pinion installation, gear ratio changes (re-gearing), locker installation, and drivetrain diagnostics. We work on Jeeps, Trucks, SUVs, fleet vehicles, RVs, and performance builds.

We also help other shops and mechanics by rebuilding complete differential assemblies (often called third members or complete units). Simply drop off the assembly, we build it right, and you pick it up ready to install. Pickup and delivery service is also available.

Call (951) 372-0200 for a same-day quote.

Services We Provide

• Ring & Pinion Installation: Precision setup for quiet operation and long-term durability.
• Re-Gearing / Ratio Changes: Ideal for 35s/37s+ tire setups, towing, and restoring power.
• Differential Rebuilds: Bearings, seals, wear parts, and complete rebuild service.
• Locker Installation: Traction upgrades for serious off-road capability.
• Limited Slip / Posi Upgrades: Better traction for street, towing, and performance builds.
• Differential Assemblies for Shops: Rebuilds of third members / complete assemblies, ready to install.
• Fleet / Commercial Service: Durable solutions for work vehicles and municipal fleets.

Choosing the Right Gear Ratio for Larger Tires

Installing larger tires can reduce power, acceleration, and fuel efficiency if the factory gearing is not matched properly. Re-gearing restores the correct balance between engine power and tire size so your vehicle drives right again.

• 35" tires: commonly benefit from ratios like 4.56 or 4.88 depending on the vehicle.
• 37" tires: often require deeper gears such as 4.88 or 5.13.
• Proper gearing improves drivability, towing performance, and off-road control.

Our technicians help you choose the correct gear ratio based on your vehicle, tire size, and how you drive.

Vehicles We Commonly Service

• Jeep Wrangler & Gladiator
• Toyota Tacoma, 4Runner & Tundra
• Ford F-150, Ranger & Bronco
• Chevrolet Silverado & GMC Sierra
• Fleet and municipal vehicles (work trucks, vans, service vehicles)
• Performance vehicles including Corvette and Viper assemblies

Common Reasons Customers Come In

• Whining / humming noises that increase with speed
• Clunking on acceleration or deceleration
• Leaks at the differential or axle seals
• Re-gear needed after installing larger tires
• Previous gear install that is noisy or improperly set up

Work Examples