Upgrading your Jeep for better off-road adventures sounds awesome, but sometimes it can cause unexpected problems. For example, when you install a Skyjacker Rock Ready-Double Flex Suspension Kit, you might notice your Jeep vibrating more than usual. That’s because the lift can mess with how the transfer case and rear axle line up. Luckily, Skyjacker has a solution called the Slip Yoke Eliminator (SYE) kit. It not only stops the vibrations but also makes your Jeep’s drive shaft stronger. In this guide, we’ll walk you through installing the NP 231 Short Shaft “Fixed Yoke” Kit. We’ll cover everything from the tools you need to important things to think about before you start. So, if you’re eager to boost your Jeep’s performance, keep reading to learn how Skyjacker can help.To improve your vehicle’s performance on trails and raise its clearance, we added a 6-inch Skyjacker Rock Ready-Double Flex Suspension Kit to the TJ’s suspension. However, this adjustment has a drawback: lifting the vehicle by just 2 inches causes the rear part of the transfer case to move up and away from the rear axle. This change increases the angle, causing a binding effect on the U-joints and creating vibrations throughout the vehicle’s driveline. This happens because the factory transfer case extends too far out and uses a drive shaft that’s too short. The vibration worsens as the suspension flexes away from the transfer case.

Solution

To fix this issue, replace the stock slip yoke with a slip yoke eliminator kit (SYE) that features a constant velocity (C/V) joint bolted to the back of the transfer case. Though dismantling the transfer case might seem daunting, don’t be discouraged from doing it yourself.

Benefits

Skyjacker’s Slip Yoke Eliminator (SYE) provides a 32-spline shaft instead of the stock 27 splines, boosting the torque capacity by 54%. This upgrade lengthens the output shaft and extends the drive shaft by 4.5 inches. These kits also feature an oil seal to prevent fluid leaks, and if the rear driveshaft fails, you can continue driving using front-wheel drive.

Kit Description

• NP 231 Short Shaft “Fixed Yoke” Kit
• Slip Yoke Eliminator Kit
• Project: 1998 TJ Jeep Wrangler
• Skill Level: Intermediate to Advanced

Kit Components

• Tailhousing, Diecast
• Main Output Shaft
• Rear Yoke Seal Washer
• Rear C/V Yoke
• Rear Yoke Nut
• Front Yoke Seal Washer
• Speed-O-Ring Gear
• Snap Ring, 207 Bearing
• 207 Open Ball Bearing (No Snap Ring)
• Snap Ring, 207 Bearing
• Mode Retainer Ring
• Tailhousing Seal

Special Note 

Installing this kit involves nearly dismantling the entire transfer case. If your transfer case has endured significant wear and tear, consider rebuilding it at this time. Before disassembling the transfer case, secure your transmission with a jack. You’ll also need to purchase a C/V type driveshaft to complete the installation. Skyjacker offers a pre-measured C/V Drive Shaft ready to install, or you can follow their instructions to have one custom made. Plan for a day to complete the installation.