TRAXXAS TRX4 Rear Aluminum Gearbox & Knuckle Kit by GPM TRX4H100R  [TRX4H100R]

Rear gearbox and knuckle upgrade for TRX4

This 54pcs aluminum kit is an aftermarket replacement set designed for TRAXXAS TRX4 scale trail crawlers, focused on the rear gearbox and knuckle arm assembly. Components are supplied to replace the rear gear box mounts, inner and outer knuckle parts, rear axle joints and shafts, plus spindle gears and a full complement of stainless steel fasteners to retain factory interfaces while shifting some mounting geometry.

Key role and fitment: the parts connect the rear gearbox to the knuckle arms, stabilise internal gearing alignment, and change the shock lower mounting positions to permit height and angle adjustments of the rear dampers. Adjustability is achieved by installing the shock lower eyelet into alternative mounting holes provided in the knuckle/box mounts.

Material and design notes: the kit uses 6061 T6 aluminum for structural pieces, with an open-style knuckle attachment for easier assembly. After installation the shock bodies sit slightly outward versus the original vertical placement, which helps stabilise the chassis and offers incremental ride-height adjustment. The knuckle internals have increased gear pitch and diameter and a lower axle centre that raises the body clearance by approximately 1.2mm as described by the manufacturer.

Use this kit when you need a lightweight aluminum replacement to stabilise rear driveline alignment and to allow small adjustments to rear shock geometry on TRX-4 crawlers; follow standard installation practices and verify clearance with pendulum-style wheels before fitting.