BD Diesel s Tugger Shift Kit for 1999-2003 Ford 4R100 transmissions  upgrades your truck s performance for hauling heavy loads and handling steep terrains. This heavy-duty kit strengthens your transmission to endure the stress of exhaust brakes and frequent downhill driving. It also provides firmer gear shifts and enhances transmission cooling, resulting in a more powerful and reliable driving experience.  Although installation necessitates a qualified mechanic due to the partial transmission disassembly, the benefits of improved performance and durability make BD Diesel s Tugger Shift Kit a worthwhile investment for hardworking trucks.