For guys with a big lift kit, in the realm of 6 inches and higher, dropping the transfer case isn’t going to cut it. The problem is the driveshaft has become too short. With the slip yoke it may be able to slide into place making impressions that it will work, but you can learn some valuable lessons the hard way if you take it out wheelin’.
A slip yoke is how the driveshaft attaches to the factory Jeep transfer case. It simply slides into place and isn’t secured with anything more than some splines on the output shaft. This is so as the suspension flexes the driveshaft can move freely, keeping it the right length at all times.
When you have a really big lift kit, the distance between the differential and the transfer case is increased and though it may slide into place it can slip out on you when you’re out in the woods. When that happens, you will lose power to the rear wheels and lose a whole bunch of fluid.
A slip yoke eliminator converts the transfer case to have a fixed mount for the driveshaft. The major benefit of this is the driveshaft can no longer slide around on you. Since these kits are meant to work with big lift kits, they are also designed to correct the driveline angle to make sure you’re not putting too much stress on your u-joints.
You also may find the factory transfer case is prone to leaking. Since these kits are designed to replace the housing extension, potential leaking issues are greatly reduced. They are also extremely durable pieces and with all the added benefits it’s pretty much a no-brainer to make this upgrade.