vangogo wrote: The new leaf springs corrected the pinon angle and got rid of the vibes.
I was also previously using the Hellwig 815 helper springs with the shackles, (to compensate for the saggy leafs) and noticed that the vibration with the shackles alone was not that bad...but when I added the helper springs it became very noticeable.
So let me see if I can get this straight.
2" shackles caused a slight vibration
adding helper springs w/ shackles made vibration worse
but removing all the above and using re-arced springs for a 3" lift caused no vibration
Is this common? Do different springs somehow keep the pinion angle correct when shackles do not? I always thought it was simply the lift that caused problems with the angle

btw: I may be interested in those lightly used shackles
