Abstract: A kit for converting the rotatable supporting structure for an intermediate gear employed in a gear box or transfer case such as those used in certain commercially available four wheel drive vehicles and the like from a loose needle bearing support for journaling the intermediate gear from its supporting shaft to a tapered roller bearing support with the kit including a pair of tapered bearing assemblies, a spacer positioned therebetween, bushings received in the transfer case bosses, thrust washers between the bushings and the bearings and a bolt-type shaft having a polygonal head at one end and a lock nut at the other to retain the components in assembled relation and to preload the bearings in the intermediate gear by applying a predetermined torque on the lock nut while holding the bolt stationary.