The GPM TXMM1137S kit is engineered to reinforce the Traxxas Mini Maxx Monster Truck drivetrain using hardened 4140 carbon steel and strong 7075 alloy components. Both front and rear complete differentials are specified with a 13T/37T tooth pairing and a 1.0mm module to increase contact patch area and reduce stress concentration on individual teeth. These material choices and dimensional values are selected to improve load capacity and wear resistance under demanding use. Differential oil is not included and should be selected based on desired limited slip behavior and operating conditions.