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