flyn289

Vehicle: 2000 Cherokee. AW4, NP231, LPD30(F), C8.25(R), xj auto front shafts (F+R), Rustys 4.5" short arm full leaf lift, 33x12.50 mt/r's(old style), 15x8 softs 8s, Rugged Ridge SYE...

Story: Had vibes with tcase drop so i decided to install sye. Went with Rugged ridge. Had sye installed by mechanic buddy. Had all new ujoint in the front shaft that would be getting used in the rear replaced. Had centering ball repacked with grease, had dshaft balanced. Got vibes with 4* shims so i went up to 6* shims. Right now the dshaft angle is at 16* and the pinion is at 13*. Get very bad vibes over 35 mph. They tend to go away when i let off of the accelerator. I do not feel in abnormal motions upon attempting to move driveshaft. have made sure output yolks are properly torqued...any ideas?

Shivelyporsche

My 99 is the exact same way. It goes away when off the gas. My pinion seal is starting to leak too.
Pinion feels tight though.
I have the HD SYE and front DS with 4* shim.

flyn289

Im trying to figure out if i need to go to 8* shims or if its an internal tcase issue potentially

cody7619

You used a front driveshaft for your rear after the SYE install? Did you have it lengthened or is it stock length?

DieselD

Could it possibly be the front drive shaft? Since you have the LP d30?

Maybe remove front DS and see if it helps. Then you could at least rule it out if nothing changes.

jeeper kyle

Yep. Pull front DS off the pinion and strap it up. See if you have any vibes.

flyn289

Still have vibes with the front shaft out. Yes i used a stock length front shaft

SDC

Check the drive shaft for any missing balance weights. You can usually tell by the clean spot.

jeeper kyle

The 3 degree difference sounds like it's too much. Get the pinion to -1 degree.

flyn289

-1 would be worse.

jeeper kyle

1 degree low to the ds. This will help with acceleration vibes caused by wrapping the axle.

flyn289

nevermind...you are saying *1 degree under as in pinion under dshaft. i cant see how 4.5" of lift would need 8* of shimming. On top of that after market full packs dont typically wrap that much. oe standards are 1-3* deviance

freegdr

Pictures says a thousand words ...

sneakyjap96

Im running 6 in lift ad sye no dagree shims an all is good running front stock dl hmm

Cherockee

It's my opinion that the axle yoke should point slightly below the driveshaft so that as power is applied, the axle will "twist" up slightly and will bring it back in line with the driveshaft. It would probably be smart to have the driveshaft checked for balance too.

A angle/degree finder is an invaluable and inexpensive tool when putting together a drivetrain.