Traxxas TRX-4 Two Speed Conversion Kit [TRA8196] - HobbyTown
CNC Alloy Transmission Gearbox Case For TRX-4 TRX4 1/10 RC Crawler Car | eBay
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AXSPEED Metal Transmission Center Gearbox Case 2 Speed for 1/10 RC Crawler TRX4 TRX6 Upgrade
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