LOSI PROMOTO-MX Transmission Inserts 7075 Alloy MX038/SP by GPM  [MX038/SP]

7075 alloy gearbox inserts for PROMOTO-MX

This replacement insert set restores the wear points inside the PROMOTO-MX transmission housing with machined 7075 alloy components that resist abrasion better than the stock plastic pieces. The inserts provide hardened seating for shafts and bearings while keeping weight low for smoother drivetrain response.

Fitting is a simple workshop task: open the gearbox, remove the worn plastic inserts, and press the alloy pieces into place. Light trimming of mould flash or a careful press fit may be needed to achieve a tight seating; use appropriate tools and avoid over-tightening adjacent fasteners. With the inserts in place the transmission holds shaft alignment under load, which helps reduce slop and supports predictable gearing behavior.

These parts are intended only for 1/4 scale PROMOTO-MX RC motorcycles and are not suitable for full-size vehicles. Confirm compatibility against the listed model identifiers before installation.