93gc40

I have some question about After Lift Drive-line Vibes.. I know a SYE and drive-shaft are the best option above 4" . Why is the answer to vibe remedies, always you need a SYE?

When we install a lift on the rear of an XJ we alter the pinion angle of the rear end. To fix this we can do the SYE, TC drop or axle shimming. If you check the pinion angle after the lift and do the fix you need? So why wouldn't the first Mod on the list be to install axle shims? Since axle is what changed, and the shims will be needed with the SYE. A TC drop works but lowers the TC up to 1" closer to the ground. I cross my fingers every time I go over a rock. Maybe a shim is all I need. Is there a chart that shows pinion angles after lifting?

xjbones

i dont use shims because the tcase output shaft and the pinion are supposed to be as parallel as possible. when you lift over 4'' you put the driveshaft at extreme angles. the cv in the new driveshaft, when installing a sye, makes that angle more gradule......less vibrations my friend

until i went huge i was running 5.5'' of lift with no sye and a 1 1/2 inch tcase drop i made with no vibrations at all. no axle shims

jd4x426

there is no set measurement as every jeep is different and you will need to figure out what you need to make it work but if all you do is the shim remember as xjbones said the angle that the stock driveshaft opperates has to be parralel with the t case and when shimming it changes which can lead to even more vibes in some instances

93gc40

But why change the DS and pinion angles at the TC, when doing the lift caused the angles to change at the Axel? The SYE seems to more a fix for DS travel than angle. The double cardon shaft just alows you to run at the increased angles. From what I understand you are still supposed to shim the axel to correct the pinion angle..