HPI Baja Rear Gear Box Alloy Upgrade BJ012 by GPM  [BJ012]

Precision rear housing compatible with HPI Baja

The BJ012 is an aftermarket alloy rear gear box specified for HPI Baja scale models. As the rear drivetrain enclosure, it locates spur gears and axle bearings and provides a robust mounting plane for the differential and adjacent drive components.

Designed as a durable replacement, the BJ012 is intended for service tasks such as swapping damaged housings, regaining correct gear mesh, and offering a corrosion-resistant alloy option over original plastic parts. The alloy structure enhances stiffness under typical off-road loads while keeping geometry compatible with HPI drivetrain layouts.

Installation notes: the BJ012 replaces the stock rear gear box using the original fastener points and internal gear arrangement. Follow standard workshop protocol—clean mating surfaces, inspect gears and bearings before reassembly, and apply threadlocker where specified by the chassis documentation.

Tuning and maintenance role: installing this alloy housing helps maintain repeatable gear mesh when addressing wear or repairing crash damage. It does not change gear ratios or require ESC adjustments, but it reduces flex-related backlash when paired with correct spur and pinion alignment.

The BJ012 is a robust aftermarket option focused on precision fit and improved durability for HPI Baja rear drivetrains, intended for workshop maintenance and setup improvement tasks.