The Jeep NP231 is one of the most commonly used transfer cases today. It is a chaindriven, planetary designed gear box with a low ratio of 2.72 to 1. For the average 4- wheeler, this is a good transfer case. One of the biggest faults of this transfer case is the overall length. At 20+ inches, this creates an extremely short rear driveshaft in the Jeep YJ & TJ Wranglers. This short rear driveline becomes even more crucial when the vehicle is lifted or a transmission swap is performed. In addition, when a lift kit is installed, larger tires are usually the next upgrade. Strength and driveline angle of the output shaft then becomes a concern.
NP231 FIXED YOKE
To make the NP231 better suited for these upgrades, we have designed our “Fixed Yoke” kit with the best features available. We manufacture a new one-piece tailhousing that will add 3-1/2 - 4” to your rear driveline length on a YJ, and up to 6” on a TJ. This will allow you to obtain a better driveshaft angle and eliminate driveline vibrations. We also manufacture a new 32 spline output shaft that is over 50% stronger than stock. This kit, along with a new 1310 series C.V. yoke, makes the NP231 a better transfer case for trail use. A full set of installation instructions is provided to assist in the installation of this kit.