Slip Yoke Eliminator Installation Purpose and Benefits
At Tom Wood’s Custom Drive Shafts, we’re proud to serve as your one-stop-shop for all Jeep driveshaft needs. We offer high-quality 4x4 driveshaft products and components for a variety of Jeep models, from the Jeep CJ to the Jeep JK, JL and many others.
One important component found on many Jeep types, including the YJ and TJ Wranglers, is known as a slip yoke. Correspondingly, you may also hear about a slip yoke eliminator, which may be installed for several potential reasons in your Jeep. Today’s blog will go over both the slip yoke and slip yoke eliminator, plus some of the reasons why you might want or need to install a slip yoke eliminator in your Jeep.
Slip Yoke and Slip Yoke Eliminator
Within many Jeeps, the slip yoke describes an internal splined shaft that’s connected to the driveshaft itself using a universal joint. The slip yoke is present to transfer power from your Jeep’s transfer case to the driveshaft, sliding in and out of the transfer case. This sliding capability allows for changing length depending on the vehicle’s movements.
A slip yoke eliminator, abbreviated SYE, does what the name suggests: It eliminates the slip yoke from the transfer case. Instead, it turns it into a fixed yoke that does not slide. The sliding component of your drive train gets moved to the drive shaft in the form of a spline stub and confusingly named slip yoke, not to be confused with the previously discussed slip yoke. This is done because the rear driveshaft of YJ and TJ Wranglers, plus certain other Jeep types, is a fixed-length shaft with a single u-joint at each end. These shafts are only designed to worth within the lengths and angles found in a stock/un-lifted Jeep. This change allows you to change the driveline length and type to account for suspension height changes. This is done by shortening the transfer case, meaning you need a longer driveshaft and a flatter drivetrain angle, in turn limiting vibration and wear on various drivetrain parts (especially for Jeeps with major lift kits installed).
Slip Yoke Eliminator Installation Purposes
Jeeps with large lift kits may experience issues with both short driveshafts and extreme angles if they are installed without changing the driveshaft. But installing the SYE converts the slip yoke to a fixed mounting yoke or flange, which allows you to properly run a double cardan driveshaft, also known as CV driveshaft. This moves the upper joint of the drive shaft closer to the rear output bearing which in turn allows for a greater driveshaft length thus reducing driveshaft angles. As an added benefit, because you are replacing the now too short stock shaft with a new double cardan shaft, you get a drive shaft that fits your lifted vehicle.
The SYE also eliminates any risk of the slip yoke sliding out too far, out of the transfer case. If this happens, you will lose power to the rear wheels and the oil in your transfer case may leak out in high volume.
SYE Vs. Transfer Case Drop
In certain cases where you’re lifting a Jeep within a certain range, you may be able to get by with just a transfer case drop – this is sometimes possible for lifts between one and two inches. However, any lift of greater than two inches virtually always requires a slip yoke eliminator installation and CV driveshaft installation, which will limit vibrations and won’t come with any of the issues often present in transfer case drops. A transfer case drop is meant to be a quick and easy way to reduce the driveshaft problems created by a lifted Jeep. It is, however, a corner-cutting solution that does not fix the problem the same way a slip yoke eliminator does.
The last piece of the slip yoke eliminator and CV driveshaft puzzle is proper pinion angle adjustment. For everything to work perfectly, the rear pinion needs to be adjusted so that it points up towards the transfer case, nearly in-line with the slope of the drive shaft. This is normally achieved by installing axle shims (for leaf spring vehicles) or by adjusting your upper control arms (for coil spring vehicles).For more on the purpose of slip yoke eliminators in many Jeeps, or to learn about any of our 4x4 driveshaft services, speak to the staff at Tom Wood’s Custom Drive Shafts today.