Originally Posted by Dan R
You wont need one, don't worry.
i wouldnt just jump to say that.....alot of people need a SYE on a 3.5" lift....esp with RE lifts which tend to be more then 3.5"...or so i've read....
First of all i'm going to assume you have a TJ
What a SYE is, is a Slip Yoke Eliminator.....not to get too in depth about it but your jeep obvisiously has a short rear drive shaft with the increase in height your also increase the angles which the driveshaft leaves the transfer case and meets the rear axle.....if this angle is to great the u-joint slightly bind creating viberations while driving.....the sye replaces the slip yoke with a shaft that remains stationary, you also buy a CV driveshaft which will extent and retract....you adjust the pinion angle to 0 (i believe) and that takes care of any binding....only way to tell if you will definately need one is to put on the lift and drive it....if you get vibes while driving even with a transfer case drop (basically does the same thing as a SYE just not as effectively) then you'll probably need one....