This center gear box is listed under part number JR-TRX423-BK, finished in black and made from aluminum. It is intended for use on Traxxas TRX-4 scale and trail crawler platforms where the center driveline housing is replaced for repair or tuning.
The unit houses the center gearset and provides the mounting interface between the transmission output and the TRX-4 front and rear driveshafts. Check chassis geometry and driveshaft alignment prior to fitting and use appropriate fastener torque to avoid thread damage.
Installation guidance: remove the original plastic housing, transfer required internal gears, spacers and bearings into this housing as necessary, maintain recommended gear lash for your TRX-4 gearset, and confirm alignment after assembly. This is supplied as an aftermarket hobby component.
Use JR-TRX423-BK when replacing the TRX-4 central housing to obtain a metal alternative; always verify installation, alignment and gear setup for reliable performance.