[JLMounce]

For confusion sake, slope is measured from the front of the car from the rear of the car when viewed from the driver's side. If the transmission output shaft slopes down from the front of the car to the rear, it's down. If the driveshaft slopes up from the trans output to the pinion, it's up. If the pinion to the rear of the differential slopes downward from the front of the car to the back, it's down. And all changes there-of.

Opposing angles, you add the degrees together. Complimentary angles, you subtract the angles from each other.

Using my car as an example, before I added pinion shims, the measurements were as follows:

Trans Output: 3.2* down
Driveshaft: 2.5* up
Pinion: .5* up

The trans output and driveshaft oppose angles, so we add them together to get a working angle of 5.7*. The driveshaft and pinion are complimentary angles, so we subtract them from each other to get a 2* operating angle. However, under load, the leaf spring will allow the pinion to rise a couple degrees. The amount of power applied will have an effect on this, but if we take an average of 4*, during power operation the pinion would have a logical angle of 3.5* down. Since that opposes the driveshaft, we'd add them together to get a 6* working angle.

In my case the working angle of the driveline itself is somewhat in spec at about .2* equal and opposing. The problem is that the individual working angles at the trans and pinion are too extreme. It's possible the driveshaft is not my vibrational culprit, which I'm trying to figure out, but with the working angles above 3* at each end, it may degrade u-joint life.