The GPM TRX4012A is a precision engineered aluminium gearbox cover designed to protect the front and rear differentials on the Traxxas TRX4. Manufactured from 6061 T6 aluminium, it provides a rigid mounting surface to reduce drivetrain movement and help maintain consistent gear mesh. The integrated oil filler hole allows easier lubricant access for routine maintenance, making this a practical performance upgrade for serious hobbyists.