Pinion Angle Adjustment Options
 

So long story short, I put a Terrafirma 2" Medium lift (no additional weight so probably a little higher than 2") on my '96 Disco and have got bad vibration right off the get go.

I've spent probably two weeks reading these boards and various threads and I have a good idea of whats going on and how to fix it. I've mocked up a drawing that illustrates my pinion/tc/propshaft angles. Hoping one of you guys that understand these trucks and their odd geometry can comment on the best action.

Here's what I know so far.

Definite propshaft vibration (not tires/balance)
Vibration is there with out the front & rear shaft removed and diff locked (vice versa)
Front is stock D1 2-joint shaft
Rear is stock D1 rotoflex (rotoflex was replaced with OEM close to 2 years ago. Visually it looks good).

Here are my ride height measurements from the top arch of the fenders to the ground (again, no additional weight e.g bumpers)

Front Left 36.25"
Front Right 35.5"
Rear Left 37" (Just Under)
Rear Right 36.5"

Looking forward to hearing from the pros. Cheers lads.

http://dl.dropbox.com/u/13036646/hot...ver-pinion.jpg

There should be no difference in the angles between the roto-flex and a u-joint.
You are looking in the wrong direction if you ar chasing a vibration, unless your diff is about to fail.
Try removing the rear shaft, if you feel this is the problem and drive in high lock on the front shaft, see if you still have the shakes.

If you have a lift of 3" or more you need to correct your angles.
You should also have the u-joints pointing up like the rotoflex, they will last longer as well as have less vibration.
U-joints can take more angle than the rotoflex but to much and they will last until you reach the end of your driveway.
I believe it is LongHaul who has done this, he has like a 25" lift and has dealt with everything you are talking about.
Shoot him a PM.

Do you have a lift, if so how much?

Yes. See here for the nightmare that is.

https://landroverforums.com/forum/di...erience-42198/

I have vibes in both the front and rear shaft after a TF "2inch" lift. Possibly cause I don't have additional weight and I'm using medium springs. So please for the love of god lets spare the the "2" you'll be fine and won't have vibes" cause I've read that 1000 times and clearly it's not a universal thing.

Why would you point the rear diff up if running a u-joint conversion? Everything I've read on driveline angle says for a 2-Joint shaft you want the TC/Tranny and diff pinion angle parallel.

I'm currently running with only the front shaft (with vibes). My rotoflex actually looks to be in pretty good condition and according to the maintenance records with the truck was replaced about 2 years ago (truck was stock ride height before I got it).

I understand that with these trucks every one is unique case, so I'm more or less just making a list of potential problems areas, making sure my theory is correct then going from there. Rather than throwing every single part at it only to still have the problem.

Yeah each truck is different for sure

EDIT.. See First Post

I agree with Mike on takeing aeach shaft out and checking for where the problem mite be.
But to answer the question The 2* difference between the tcase and the diff I cant see that being an issue. If you go to Tom Woods driveshafts website in the tech section they have a very good article on angles and driveshaft slopes.

I've already done that. Vibration exists with both shafts. I made some measurement errors. I've updated the OP.

The only thing I see wrong with the angles is the rear of the tcase is 0* and the front is 4* im wondering if the bearing is bad on the output of the front of the tcase??? everything else seems to be well within reason. The front and rear output of the tcase should be matching #s.