Drive shaft angles and shims

I did a search and I think I have this figured out but I want some input and advice. Here's my vehicle specs: 93 4.0 auto and 231 w/8.25, I currently have approx. 4.5"of lift w/1" TC drop.
My angles are like this:

transfer case is at 5*
Driveshaft 15*
Rear is at 6* normal, under acceleration it goes to 8*

From the search I did I will need a 2* shim fat side facing the front to keep the angles even under normal acceleration. Does this sound right?

My vibes are minimal and with the M/T tires I really can't tell what range I have them anymore. I just want to correct the angles for ease of mind. Hopefully by summer I will have my SYE and DS. I also wanted to see what would happen long term from driving with vibes. Only thing I have noticed is a leaky rear main. But who knows what is going on inside. Thanks for all the help and advice...Doug

family XJ said:

transfer case is at 5*
Driveshaft 15*
Rear is at 6* normal, under acceleration it goes to 8*

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Hmm..... wouldn't you be better off to limiting/eliminating axle wrap?? Cause if you fix the accelaration I think that you will end up with vibes at cruise speed as your angles will be off again? Btw, I'm kind of curious: how did you measure your accelaration angle

Btw, do you have blocks ? spring pack? AAL? or longer shackles?

I could measure the acceleration angle by looking at the slip yoke and seeing how much shiney silver was showing then by placing a jack under the front of the pumpkin and raising till the silver diappeared. As for my lift I have a full length AAL and 1" block. I was thinking about building something to limit the axle wrap. I really think that would make for the best results as well. I just don't have time to build anything. I am military and a contractor in my off time. Thanks for the help.

family XJ said:

I could measure the acceleration angle by looking at the slip yoke and seeing how much shiney silver was showing then by placing a jack under the front of the pumpkin and raising till the silver diappeared. As for my lift I have a full length AAL and 1" block. I was thinking about building something to limit the axle wrap. I really think that would make for the best results as well. I just don't have time to build anything. I am military and a contractor in my off time. Thanks for the help.

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Ok, I think that the biggest culprit you have is the lift block..... try swapping out the block for a longer shackle to achieve the same thing. For one the shackle will change your angles a bit, and also it will not be as prone to axle wrap..... cause if you shim to account for axle wrap, what about regular driving when you're not accelarating or you're decelarating? Those angles will be off

What if you have A 3"AAL, 1" block, and 1.5" shackles w/1" Tc-drop,No SYE. I have that on my 2000 xj and I have very little vibes and I think a 2 deg shim will stop it all together. :farmer: Rob B Y2K-XJ

Rob Bolin said:

What if you have A 3"AAL, 1" block, and 1.5" shackles w/1" Tc-drop,No SYE. I have that on my 2000 xj and I have very little vibes and I think a 2 deg shim will stop it all together. :farmer: Rob B Y2K-XJ

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ok... so you got close to 4.75 inches.... well... how's your shaft? When you droop make sure it doesn't fall off (it's been known to happen)...... In any case, beware of the pack dying on you as with teh combination of AAL and the block and shackles you're stressing it... and it will do to you what mine did to me: it will start to bend right were the first leaf under the main ends.......

The shaft is fine I think , I just changed the U-joints, it wheels just fine and at full droop it seems to stay put for now anyway.. I know the setup I got aint proper ,plan to do the 8" full packs eventually and 7.5" coils in front and call it good! Rob B Y2K-XJ :smoker:

If your at 4.5 with a SYE you could ditch your tcase drop get that 1" back from that and go with a 6* shim thats what I have on my 01 and have 0 vibes at any time. the SYE and the shims really take away the harsh *'s.

Just an option.