1980firstgen20r,

What do you think is causing your vibrations?

When do you feel the vibrations?

If the vibrations are caused by out of phase U-joints or driveline angles, it’s usually a fairly straight forward fix.

If the vibrations are caused by bad U-joints, or pinion bearings, they usually can be detected by checking for excessive movement.

Some axle wrap is normal.  Excessive axle wrap may occur  on heavy acceleration, braking, and on the trail while applying lots of throttle torque, like rock crawling.

https://www.drivelinesnw.com/part-trouble-shooting/vibration-analysis/angle-analysis/measuring-and-correcting-angle-problems/

https://www.4wd.com/p/pro-comp-degree-shim-99-200/_/R-DFCW-99-200?utm_source=google&utm_medium=cpc&utm_campaign=shopping&emlprox=out&ppcfon=1&gp=1&scid=scplpEXP99-200&sc_intid=EXP99-200&gclid=EAIaIQobChMInefJv_rO1QIVgYl-Ch18MgRZEAQYBCABEgLnsPD_BwE


Gnarls.