This kit is a MUST if you installed a 2” or taller suspension Jeep in your 1987-2006 Wrangler (not needed for body lifted Jeeps). The kit fits all newer production NP 231 transfer cases (1988up). A Slip Yoke Eliminator Kit will eliminate the need to drop your transfer case in order to avoid drive train vibrations that are caused by taller suspension lift kit. The purpose of this kit is to replace the slip yoke portion of the NP 231 with a fixed-yoke, CV style drive shaft assembly. This is the most complete and strongest kit available. Check out the size and thickness of the output shaft housing. NOTE: A CV equipped drive shaft will be required for this conversion kit.