Includes The RPM Hybrid Gearbox Housing and Rear Mounts for Traxxas 2wd vehicles is designed to solve a multitude of issues with stock and other aftermarket transmission housings. Their gearbox housing and mounts are a blend of aluminum and molded nylon parts for the perfect combination of strength, durability and heat dissipation. Check out this awesome list of included features: Aluminum Motor Plate: Manufactured in the USA from 3mm thick, 6061 T6 aluminum for serious strength and durability. Locks in gear mesh for worry-free pinion to spur settings, eliminating fears of exploding spur and pinion gears from an overheated stock transmission case. Offers significant motor heat dissipation for cooler motor temperatures, unlike stock plastic motor plates that insulate the motor. Not integrated with the rear bumper mounts, meaning rear impacts will not bend the motor plate, (when used with a rear bumper or bumper mounting system such as RPM #80902 or #80905). Molded Gearbox Housings: Molded from RPM's blend of bulletproof nylons for guaranteed durability, strength and style. Retains stock bumper mounting holes for positive, solid support of any bumper or wheelie bars you may choose. Retains a stock "cover" for the motor, adding motor protection where most aftermarket housings leave the motor completely exposed to rear impacts. RPM modified their housing to eliminate the huge bottom hole in the stock housing, keeping your internal gears cleaner longer. Quiet! With a completely enclosed gearbox housing, you'll no longer have the loudest transmission on the track. Redesigned exterior features are smoother; making it less likely dirt will adhere or build up on the case. Separate housing and rear mounts means transmission maintenance won't affect suspension settings. Molded Rear Mounts (0 degrees & 3 degrees Rear Mounts Included) Separate from the gearbox housing and easy to access. Each mount is individually accessible and removable without removing the transmission or vice versa. Simply unbolt 2 screws (and a hinge pin) to remove an A-arm mount or 6 screws to remove the transmission! Sold with two sets of rear mounts in each package-0 degree and 3 degree rear mounts are included. Molded from the RPM blend of ultra durable, long lasting, bulletproof nylons. Molded mounts means tighter tolerances and less slop than with machined components for better camber and toe angle retention.Each RPM Gearbox Housing kit comes will all necessary mounting hardware and instructions. Whether racing or bashing, the RPM Gearbox Housing is one of the least expensive yet most valuable options you can buy! Tech Notes: RPM Gearbox Housings do not include internal components (gears bearings, shafts, etc.). Internal components (either stock or aftermarket) must be transferred to the RPM Gearbox Housing from the stock Traxxas transmission. RPM Gearbox Housings replace stock Traxxas #3691 (or #3691A). Tech Notes: The RPM Gearbox Housing and Rear Mounts replace stock Traxxas #3691 and #3691A. Due to the amount of strengthening material we added to the rear mounts, some modification of stock a-arms may be needed to allow free suspension movement. This slight interference issue is nonexistent when used with RPM rear a-arms.