I was recently told that it was bad to run shims under your leaf spring because it changed the axle angle from the t-case. He said that the t-case should be parallel no matter where it flexed. And that it cause axle wrap and a funky vibration/binding whenever you hit the gas. <-- i do have this but i just wanted to know if i should take them out or not. Even if i took them out i would still have Driveline vibration? And i do have SYE and CV driveshaft. Anyone help me with this?

 

This is incorrect. Since you have an SYE your DS and rear axle pinion should like up perfectly (180 degrees), that's the point of shims. Shims will not cause axle warp (or at least not noticeably). Axle warp is caused by people that put 10 inch blocks under their leafs. The reason you have vibrations in the drive line is prolly cuz you have the wrong "degree" shims. Take them out, measure your pinion angle, do some geometry, and get yourself the correct shims.

Also, that part about the t case and pinion always being parallel... that only applies to people that do not have SYE's

 

SO i have a 4.5" lift but i only have 4 degree shims so should i get maybe 5 degree shims?

 

Idk, take them out. Bolt everything back up, measure the pinion angle, order new shims.

I can't tell you exactly what angle shims to get cuz every jeep is different.