GPM Racing 4140 Carbon Steel + 7075 Alloy Front & Rear Complete Diffs & Upper Bulkhead & Diffs Housing for Traxxas 1/6 4WD XRT 8S-78086-4 (XRT1213KIT)

Metal Differential and Upper Bulkhead Kit

This aftermarket kit replaces the stock front and rear differential assemblies and upper bulkheads on TRAXXAS XRT 8S platforms. The differential bevels and pinions are machined from 4140 carbon steel with heat treatment to enhance torsional strength and wear resistance. Housings and the front/rear upper bulkheads are CNC machined from 7075-T6 aluminium to increase rigidity while keeping weight reasonable. The kit is designed for heavy-load and repeated-jump RC operation, offering a direct-fit upgrade focused on drivetrain durability and consistent handling under stress.

Key drivetrain details include a 32T diff bevel gear, 10T pinion gears, and components to module M1.6. Bearings and gaskets required for the assembled differentials are included to facilitate swap-in replacement of factory units. The hardened steel gears and alloy housings stabilise differential behaviour during high torque bursts and reduce wear on plastic factory gears by relocating loads to stronger materials.

Compatible Models

• TRAXXAS 1/5 X-Maxx 8S 4140 Carbon Steel + 7075 Alloy Front & Rear Complete Diffs & Upper Bulkhead & Diffs Housing – GPM XRT1213KIT
• TRAXXAS 1/6 4WD XRT 8S-78086-4
• TRAXXAS 1/5 X-Maxx 8S Ultimate-77097-4
• TRAXXAS 1/5 X-Maxx 8S Monster Truck-77096-4
• TRAXXAS 1/6 XRT Ultimate 8S-78097-4
• TRAXXAS 1/5 X-Monster BIGFOOT 50th-77136-4
• TRAXXAS 1/5 X-Monster Chassis Monster Truck-77036-4

Suitable for builders who prioritise increased drivetrain longevity on 1/5 and 1/6 TRAXXAS platforms, this kit offers a material and durability upgrade without changing vehicle geometry.

Is special maintenance required after installation?

Inspect gear mesh and bearing preload after initial break-in and at regular intervals; replace gaskets if seals show signs of wear.

Can these parts be used for competition or heavy recreational use?

Yes. The 4140 steel gears and 7075-T6 alloy housings are intended to better withstand the demands of heavy recreational and competitive driving compared with factory plastic components.

Are all required fasteners included?

The kit ships with the bearings, gaskets, and the grade 12.9 screws specified for assembly; verify contents against the packing list before starting installation.

Any recommended setup checks before first use?

After assembly, confirm all fasteners are torqued correctly, check gear mesh and backlash, and perform a low-power run-in to ensure smooth operation before full-power testing. Write Product Review Please sign in your account before you can write any review. Sign In Close

Made to order: GPM Racing parts are shipped to us from GPM’s factory, so please allow around 14 days for dispatch.