This is the culprit. Picture make it look taller than it is for some reason.



History is, I bought it for 500.00 as a non running project. Cut out both front and rear stock suspension and converted to leafs.

Converted the auto to 5spd and dual gear drive cases. The rear case is 4.7 w/twin sticks.

Diffs are both 5:29's with Detroit's (new)

Has new drive line 43" long w/cv

Here is the pinion angle with a cv drive line.


I have a vibration that I feel in the seat under load at mostly 50mph and faster. When I say load I mean when accelerating and decelerating. I can cruise on flat ground with no real noticeable problem.

I think it is coming from the rear because the front end is unlocked so that shouldn't come into play.

Front springs are 3'TG with anti death wobble 41/2 shackles
Rear springs are 5" allpro with the anti wrap leaf with 41/2 shackles.

I have tried the following;
Different tires
Stock rear third
New drive line That makes two with no change
Took the transfer cases out and rechecked them and they seem ok.

Any Ideas? All Help appreciated

 

You have a modded drive shaft? it kind of sounds like unbalanced driveshaft or something close to that...

 

Sounds like an unbalance drive shaft.

 

I had the front IFS cv re tubed to make it fit the rear. It has been to two shops and they both say it is balanced? I am thinking about realigning the perches and putting a non cv shaft on?

 

hmm, you mean a propeller shaft right? and your cv mounts at both ends are both put on exactly at the same angle? n how come you chose to use the front shaft 4 the rear/?

 

I don’t know what a propeller shaft is, but mine has a double cardain? (Spelling) on the tcase side with a regular u joint at the pinion. It was my understanding they ran smoother.

 

so everyone think it is drive line?

 

Bad ujoints or dshaft not balanced.

:wabbit2:

 

I've tried two drive lines both totally rebuilt.

 

Snug up all the suspension bolts/nuts, especially on bushings.

:wabbit2:

 

Yep, all new bushings in springs, anti death wobble shackles.

 

All new doesn't mean tight enough.

Try some balanced street tires.

:wabbit2:

 

There're tight and I've tried other tires. I'm thinking maybe rear tcase output.

 

so did you ever fix your vibration issue? another thing i thought about is when the driveshaft was re assembled that slip joint could or one of the u joints were put out of phase... i hope you were able to fix it already though

 

Yep, got it fixed. Third driveline was the charm.