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

7075 alloy transmission inserts

This is an RC-scale replacement insert set for the PROMOTO-MX transmission housing, supplied as a small kit intended to restore wear points inside the gearbox area. The parts are machined from 7075 alloy to provide improved wear resistance compared with standard plastic inserts, and they serve as lightweight, durable contact surfaces where shafts and bearings seat in the transmission housing.

Installation is straightforward for model-level maintenance: remove the transmission housing, extract the worn inserts, and press in the new 7075 alloy pieces. Minor trimming of housing flash or careful use of a light press may be required to ensure a snug fit; use suitable tools and avoid over-torquing surrounding fasteners. These inserts assist tuning by maintaining consistent shaft alignment under load, which can reduce drivetrain slop and support repeatable gearing behavior.

Do not use these parts on full-size vehicles, they are designed only for 1/4 scale PROMOTO-MX RC motorcycles. Compatible model identifiers are listed below, please confirm fitment against the model codes before installation.