At about what amount of lift does a sye come into play?

 

From what i understand, anything over 4.5" it is needed..

 

Every jeep is different... Some need it at 3 inches and others can lift 4-6 inches with no vibes. In general though the older models are more lenient. There is no "At this point you'll need a sye"

 

Ok i have a 3" on mine and it doesnt vibrate at all even wen i top out the speedo. Im wanting to put a 4.5" with 32-33 tires. Will the wider tires have any effect on vibration

 

Vibs will come from incorrect drive angles not tire width.... If your good at 3 inches with absolutely no vibes than you'll "probably" be okay at 4.5 with a 1 inch TC drop. I'm kinda new to this as well but I think 6 degree shims work well with a 4.5 lift to help correct your angles and will probably come with whatever kit you go with...

 

Wonderful

 

Yup..4.5" and above.

 

I have a 4.5" with a 1" tc drop and I have no vibes whatsoever. HOWEVER vibes are not the only purpose of the SYE. As your suspension moves up and down your yolk slides in and out of your transfer case. If it moves down far enough, the yolk could actually come out of the transfer case, spilling all of it's fluids on the ground. With my 4.5" like I said, there's no vibes, but there is a perfect splash line in the tunnel over where the yolk is slid out some, so I am losing some fluid there. An SYE is a good idea at any lift because it fixes the yolk to the shaft and therefore can not slide out. Instead you'd use a different driveshaft (usually a front driveshaft out of an XJ or ZJ) that is extendable.

 

well said buddy..