The GPM Aluminum Outer Portal Drive Housing for Traxxas TRX4 is engineered to stabilise inner gears on both front and rear knuckle arms, reducing lateral play and improving gear mesh consistency. Fabricated from 6061 T6 aluminium with a precision-machined finish, the housing is a durable, lightweight replacement for the original plastic components and retains compatibility for plug-and-play installation. The 3D streamlined form factor assists with alignment and helps maintain smooth gear operation under load.