The Dynatrac Free-Spin Heavy-Duty Hub Conversion Kit for 2000-2008 Ram 2500 and 3500 trucks is designed to replace the factory unit bearings with fixed spindles for superior strength and smooth performance. Factory unit bearings are not serviceable, can’t be inspected, and are a known failure point. This kit fits both single-rear-wheel (SRW) and dual-rear-wheel (DRW) trucks. It also ...