Update : Got the drive shaft angle spot on now, pinion angle 1 degree lower. Still have a vibration. I ran the Jeep up on jack stands and found the vibration to be coming from the tcase it self. Bad bearings? Or what could it be its got almost 300k on it now. Should I just go a head with a rebuild kit?Also I ran it with the drive shaft connected and without it, still the same vibes.

 

pull the front shaft and see if the tcase is passing the vibes

 

Still does vibe, Ive been running it for the past week with it off. I have it on currently and still the same vibes as it was with it off.

I wouldnt even call it a vibration really, its more of a low end growl then anything.

 

do you have four jack stands? if you can lift all four corners, you have a helper work the gas while you crawl around and look / listen / feel for the problem

obviously it will kill you if it falls so you need four stands not jacks or bricks or anything

 

Don't do this. I personally have known 3 people that followed the letter of the law on lifting a car in the driveway and supporting it with jackstands, all dead now. Do the safe thing and take it to a shop and have it put on a proper lift IF you decide to do this.

 

DAYUM!

 

We have 4 massive stumps.. about 30" diameter, flat on the bottom and all the same height. Cut a grove with the chainsaw to hold the frame. Use a couple hi-lifts to lift the jeep onto them. That is what I use when I'm going to be pulling/yanking on things. (swapping axles even) Jack stands are great for changing a tire etc. But they will fold easier than you think... tons of people use them no problem and without injury but I don't trust them- especially not alone.

 

needs to keep weight on the axles for drive line angles to stay relevant

 

A few posts back I said,

I ran the Jeep up on jack stands and found the vibration to be coming from the tcase it self. Bad bearings? Or what could it be its got almost 300k on it now. Should I just go a head with a rebuild kit? Also I ran it with the drive shaft connected and without it, still the same vibes.

 

Did you run with the front or rear drive shaft out? Try running just the front, rear removed, and see what happens.

 

I ran it on jack stands with the rear on and off same vibes, when on jack stands the front wont turn unless its in 4 wheel drive anyways.

I have been driving for a week on the streets with no front drive shaft in and its the exact same with it in.

 

correct. the 1-3* is typically to account for twist in the leaf springs under acceleration

driveshafts are actually supposed to be clocked a certain way. it helps with joint longevity and possible vibration. the ears of the yokes should be on the same plane on both ends of the shaft. they should already be this way unless you have removed the telescoping portion and put it back on. not a huge deal, but may help with vibration

 

[QUOTE="Atmos;3060045"] correct. the 1-3* is typically to account for twist in the leaf springs under acceleration driveshafts are actually supposed to be clocked a certain way. it helps with joint longevity and possible vibration. the ears of the yokes should be on the same plane on both ends of the shaft. they should already be this way unless you have removed the telescoping portion and put it back on. not a huge deal, but may help with vibration[/QUOTE
Thx for the info. Bought a 99 with a 4.5 zone lift a few months back. Can't drive over 55 without a lot of vibes. Trying to gather all the info I can to fix it

 

As for the transfer case, assuming its similar to my NP242. The input is attached to a short shaft, and the output has a longer shaft that inserts into a cup bearing in the input shaft (loosely coupled). The shaft splines are directly engaged in 2WD and 4WD Hi, indirectly engaged via planetary in 4WD Lo, and disengaged in Neutral. There are large ball bearings at each end of the housing that prevent them from flopping around, and snap rings that prevent the shafts from moving in and out. Vibrations in the case could be a result of bearings or rings failing to hold the shafts in position, or could be a dirty/broken bearing that is making roughness. You might be able to check if the vibrations are specific to a mode selection. Have you checked the fluid level?

Could also be that the motor mounts or transmission mount is bad and allowing the powertrain vibrations to pass all the way through to the transfer case.

 

The transmission mount was just changed a week ago, motor mounts seem to be fine no cracks or anything. The pinion angle is now 1 degree lower than the drive shaft. I am going to check for run out on the yoke at the tcase tonight. If not that my local Jeep shops has offered to check it out and repair it for a good deal.