angles on driveshaft / u-Joints stock leafsprings with caltracs

Buschi340 said
ok, thanks a lot. Will start today bringing the tranny in Position and measure pinion where i am. Now it sounds easier than all those Internet reading :) 3° down tranny, 2° down pinion.

guess. If i jack up those assumed 5° travel on the pinion ( simulating load ) I should achieve equal angles on both sides of the drive shaft... right?

Whether the drive shaft has equal angles isn't what all the "pinion angle" web sites are saying, although it might be one way to check. What they do say is that when the rear end is under load (acceleration) the pinion should rise up at which point the eng/trans drive line and the pinion center line will be parallel. It's really hard to tell how much a particular pinion (rear suspension) will rise and that's why there procedures to "dial it in":

"" Checking to see if you have got it correct:
If there is no vibration under normal operating conditions then the angles are correct.
If there is vibration under acceleration, you need to add more downward pinion angle preload. If the opposite occurs, the vibrations tends to decrease or disappear under acceleration, you need to reduce the downward angle preload.

If the vibration steadily increases with driveshaft speed (either accelerating or decelerating) the symptom is primarily the result of a driveshaft imbalance or yoke runout. Sometimes this yoke runout problem can be improved by rotating the U-joint 180-degrees in the rear end differential yoke.

Driveshaft-related vibrations usually occur at roughly engine speed in high gear. Wheel/axle vibrations usually occur at 1/3 rd engine speed or driveshaft speed because of the differential gearing. To determining whether it is the output of the transmission or the pinion in the differential, change gears when the noise occurs and maintain speed. If the vibration/noise changes in frequency, the source is in the transmission or engine. If the frequency remains the same it is a driveline problem.""

You can also look here:

Determining Engine and Pinion Angle

Drive Shaft Harmonics

Setting Pinion Angle | Hotrod Hotline

That's why they make "angle shims". The factory had engineers and test facilities to "dial it in" perfectly so that new cars have no vibration in the drive line. Us Hot Rodders have to do it in steps and the angle shims let you get it perfect because you never really know exactly how much your pinion will rise. You also need to realize that the pinion will rise different amounts (to some degree) depending on whether you're launching off the line (drag racing), casually leaving a stop sign in town or stomping into passing gear at 55MPH.

Treblig