question about vibes

anlo

Registered User
okay just changed out mounts on the ladies 90 with awesome results of course but have picked up a vibration that wasnt there before as ive read due to the lifting of engine to original height could have changed the dynamics of the drive shaft . the vibe is at the point between accelerating and decelerating that place right in between not completely coasting but not giving gas. worse at higher speeds but can be noticed at lower speeds... the question is being that i did not change tranny mount could this be the culprit or worn u joints all seems to be tight . i will probably change out both but wondered if any one knew if this symptom was related to either or both ?? tailshaft could be in the mix but dont think thats the case ...after changing all three mounts on the 95 i did not notice this issue actually reduced some vibration... so any suggestion would be appreciated...
 
I'm familiar with that. When I had the problem before, it was due to worn bushings in the rear suspension. In particular, the upper/inner eccentric bushings. I've also had vibration from worn out upper knuckle bushings and lastly from an out of balance driveline. I fixed the driveline problem by "indexing" the driveshaft where it bolts up to the differential. The technique is to raise the rear on jackstands and run it up to 70 and note "better or worse", stop, shift the bolt pattern 90 degrees and repeat until the least amount of vibe.

Note.. block the front wheels, put the stands under the LCAs.. not the frame so that the wheels are at normal ride height, and very easy up/down on the throttle since the driveline is unloaded. Slowly apply throttle and slowly let off. Oh.. and stay out from under the car of course when testing.
 
yes

that makes some sense as i was under inspecting things a few of those bushings looked dry rotted not great shape. thanks i will check it out.
what would be the technical term for these bushings and where would you find them?
 
Last edited:
mounts

solid rubber all the way around on the 95 and does have some vibration 60-70
on the 90 solid also just didnt do the trans mount on it..
i want to learn more about this drive shaft indexing whats that about ?
 
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