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

Rear gear box for HPI Baja

The GPM BJ012 is an aftermarket alloy rear gear box designed for HPI Baja scale RC models. It serves as the rear drivetrain housing that secures spur gears and axles, and provides a rigid mounting point for the rear differential and related drive components.

This part is intended for hobby-level replacement and service tasks: swapping out worn housings, restoring gear mesh alignment, and providing a corrosion-resistant alternative to stock plastic components. The alloy construction improves structural stiffness under common off-road loads while keeping the component focused on RC-scale use.

Installation notes: the BJ012 installs in place of the original rear gear box and uses the existing fastener locations and internal gearing layout of the HPI Baja assembly. Standard workshop practice—clean mating surfaces, inspect internal gears and bearings before reassembly, and use threadlocker where specified by the chassis manual—applies.

Tuning and maintenance role: replacing the rear gear box can help maintain consistent gear mesh when chasing drivetrain wear or after a crash. It does not change gear ratios or electronics behavior, but it can reduce flex-related backlash during heavy throttle and terrain impacts when combined with correct spur and pinion alignment.

The GPM BJ012 alloy rear gear box is a direct aftermarket replacement focused on structural durability and consistent drivetrain alignment for HPI Baja RC models; use it as part of routine drivetrain maintenance and setup adjustments.