http://spicerparts.com/calculators/d...gle-calculator

This helped me a lot to correct the angle after my lift.

 

How did that help you?

 

I got to see the effect of changing different angles like a TC drop or different pinion angle shims without really changing anything until the angles were correct. I measured the angles I had AFTER the lift then changed things on the calculator to see the effects and come up with the correct changes. Some people said they use 4 degree shims on the springs. When I plugged in that number those really are the most helpful shims so I ordered those. I just need good drive line angles for a stock driveshaft at this moment in time. A 4 degree shim with a 1 inch TC drop should work out well for me. Every rig is different. This gave me numbers specific to my rig.

 

Something is not right. Stock driveshaft, replacement springs without lift, four degree shims and TC drop?
4* shims work well for my 4.5" lift with SYE.

 

I measured the angles after the lift not before. I measured the angles after the lift. Then I used the calculator to discover how to correct the drive angles. I put a 3 inch lift on which wound up actually being 3.75 inches. Anyway it worked perfectly and I have no vibration.