rear drive shaft angle

just got my rear drive shaft re-ujointed and balanced and its deniflty the angle of it that is causing my vibes cause when i take it off i have no vibes at all.

how do i messure what angle i should be running? what angle should i be running at?

FYI ive got

RE hack n tap + double knuckle drive shaft
3.5 rear leaf springs
1.5 inch lift shackles

thanks! -bill

I assume by double knuckle you are refering to a double Cardan shaft that bolts up to the SYE flange. That being the case, you want the rear axle pinion shaft in a straight line with the drive shaft. I had a small angle there after I installed my 9" and it did cause vibrations. Corrected it with different angled shims- no more vibrations