TRX-4 Rear Gearbox and Knuckle Kit, 54pcs 6061 T6 - TRX4H100R by GPM  [TRX4H100R]

Aluminium rear gearbox and knuckle upgrade for TRX-4

This 54pcs aluminium kit is an aftermarket replacement set made for TRX-4 scale trail crawlers, concentrating on the rear gearbox and knuckle arm assembly. The bundle replaces the rear gearbox mounts, inner and outer knuckle sections, rear axle joint and shaft, spindle gears and includes a full set of stainless steel fasteners to keep factory interfaces while altering some mounting geometry.

Fitment and function: these components link the rear gearbox to the knuckle arms, maintain gearing alignment and move the shock lower mounting positions to allow small adjustments to rear damper height and angle. Adjustment is achieved by installing the shock lower eyelet into alternative mounting holes provided on the knuckle and box mounts.

Materials and design: structural pieces are machined from 6061 T6 aluminium with an open-style knuckle attachment for simpler assembly. Once fitted the shock bodies sit slightly outboard compared to the stock vertical placement, improving chassis stability and providing minor ride-height adjustment. The knuckle internals use a larger pitch and diameter and a lower axle centre that increases body clearance by about 1.2mm as noted by the manufacturer.

Choose this kit when you want a lighter aluminium option to stabilise rear driveline alignment and to permit small changes to rear shock geometry on TRX-4 crawlers; follow standard installation practice and check clearance with pendulum-style wheels before fitting.