Aftermarket driveshafts are usually needed to help eliminate drive train vibrations on lifted Jeeps. Most Jeeps older than 2007 will usually require a SYE Kit (Slip Yoke Eliminator Kit) or some method of a transfer case crossmember drop to correct the steep angle that is created after the installation of an aftermarket lift. All SYE kits and driveshafts are not built the same. Watch out for cheap junk that others sell. The driveshafts we sell will only use genuine Spicer u joints or a Tom Wood's aftermarket HD Joint depending if that is the vendor chosen at the time of placing the order. Typically driveshafts are spin balanced at over 100 miles an hour with a full contact 7" slip and spline(If applicable). For technical help please feel free to email or call. These driveshaft upgrades are built to the highest quality for years of 4x4 adventures. All driveshafts we sell are competition proven, trail tested and built to show quality.