Go to http://4xshaft.com/
Halfway down the page Technical Information and Sponsorships grey banner. Go in their and do some reading before you get all wrong on this. Here are a couple of pictures to help out.
Which driveshaft do you have pick the right picture and get your pinion angle lined up like the picture.
It works and with an angle finder you need to know the right angles and be within 2 degrees low to account for axle wrap on start up.
89YJ 2.5L TBI, AX-5, NP231 SYE, Ford 8.8, Yukon Grizzly, Tom Woods Shaft, 33" BFG T/As, 4" lift, Warn VR10000s.
AF Jeep Club Tail #184