vibration...but not always

[green67cuda]

vibrations.....gotta hate 'em.

OK...i have a strange vibration thing going on that i have NEVER seen before....only at 55+ i get a vibration sometimes. i notice it most on the interstate, about 65-75 mph. the car will be fine, and i can hit a rough spot in the road, and the car will get this terrible vibration.....a fast vibration, not a rumble. then it will go away after a couple of minutes....or it will go away if i goose the throttle and let off......until i hit a rough spot again.
i thought maybe tranny mount, so i made sure it was nice and tight.....all's good there.
It seems to have started when i put on the S/S springs, because i never noticed it before.

oh, and i can feel it MOST in the seat. and sometimes it starts even without hitting a bump or rough spot, but mostly when i do.

 

[Mrmopartech]

I would check the pinion angle and the u-jionts for binding and for excessive angle.Your jiont could be at too much angle causing the vibration.it can be adjusted with the mopar shims,but first check the joints and do the angle check with a meter,mrmopartech

 

[Duster346]

Hey RW,

sounds like maybe a shock or worn suspension part, if the vibration starts only after you hit a bump.

I know I've seen a fair share of nasty vibrations due to worn shocks and/or steering dampers (on 4wd trucks).

hope this helps some, post what you find.

 

[340fourspeedDuster]

I second the pinion angle.

 

[green67cuda]

hmm.....just got done for the night....i'm working on a panel for the former rear seat area.
while i was out there, i got out the angle finder.....seems the S/S springs took out the 5* i put in when i welded the perches on in the winter.
had zero degrees with the car sitting on all 4s. i had some 4* shims on the shelf and put them on though, so we'll see how it does tomorrow evening on my way to work.