To prevent driveline vibration, a Rough Country rear double cardan style CV driveshaft is recommended for Wrangler models with 4" or more of suspension lift. Not only will this prevent driveline vibrations, but will prevent the rear output shaft from breaking. The Rough Country driveshaft is twice as strong as the factory driveshaft. It includes better quality CV joints and the grease fitting are out of the way of the transmission oil pan making it easier to get grease to the joints that need it and not all over the bottom of your Jeep.