TRAXXAS Differential, front (complete with pinion gear and differential plastics) (fits 1/10-scale Rally & 4X4 VXL models: Slash, Stampede, Rustler) (13/37 ratio) 38-6788 Description: The Pro-BUILT 4X4 front differential comes professionally assembled for easy drop-in replacement. The sealed assembly comes pre-filled with 30k-weight silicone oil with steel gears to withstand Velineon brushless horsepower. Pro-BUILT differentials are direct replacements for VXL 4X4 models (see full list below). Includes 13-tooth pinion gear and 37-tooth ring gear. Pro-BUILT differentials are not directly compatible with Titan-powered 4X4 models. Accessory part for these models: Ford Fiesta ST Rally Hoss 4X4 VXL Rustler 4X4 VXL Slash 4X4 Ultimate Slash 4X4 VXL Stampede 4X4 VXL