About this item Function – Mainshaft 5th Gear Nut Wrench is a necessity to remove or install the mainshaft nut, it fits for Dodge NV4500HD 1994-2004. Application – Required for all in-vehicle and bench repairs that involve mainshaft service, including mainshaft fifth gear replacement. Fitment – Fits Dodge NV4500 4×4 29 spline & 4×2 31 Spline output New Venture NV4500HD models (Cummins Diesel or V-10). 1/2″ Drive. Compatibility – NV4500HD transmission used in Cummins and V10 powered Dodge RAM models have a large diameter mainshaft nut. Material – Made of high quality steel and features a fine textured black powdercoat finish for lasting durability.