Transfer Case Vibration Issue

[loveofjazz]

Durnzuki may be on to something with axle wrap.  it can cause the u-joints to work at an angle past what they are designed to do, and cause a vibration.  incorrect pinion angle can add to this problem.  Good luck.

Yeah, I'm not ruling ANYthing out, and I know Jeff, Richard, Jason and Ken have all offered good info. I'm doing my best to follow all valid suggestions offered up (as time allows). I've posted this here in hopes that fellow Zukers that have dealt with this will weigh in on the subject. I'm starting to believe that this could be a combination of things.

If it turned out to be an axle wrap issue, I only know of two ways to resolve it currently...
  1. Install a traction bar
  2. Modify my rear springs (CJ fronts) by adding a leaf to each spring pack. Maybe I could add a leaf out of some of the older Samurai front packs in the garage to stiffen the rear springs. Would that work?

[Surly]

Would that work?

Remember, a stiffer spring will give you a harsher ride.

A better solution would be to rotate the pinion flange down 2 degrees from parallel with the t-case flange. Then the angles will be parallel under torque.

[tonkatoy]

I had the same problem. I will tell you what stopped mine was the rubber adapters between the transfer case and the bracket. They where still together but very spongy or loose you might say. I put some new ones on and the vibe stopped. Good Luck I hope this helps you!!

[zuki scott]

you have checked that the u joints are aligned on the rear shaft haven't you. meaning phased correctly

[tonkatoy]

Thats the way I found out that is was the rubber things where bad. I checked the phase and replaced all u-joints. Nothing changed until I replace the rubber things. It fixed mine. It took 6 months to find it. All good now. Shawn

[madbob]

you have checked that the u joints are aligned on the rear shaft haven't you. meaning phased correctly

good call

[loveofjazz]

I am betting on axle wrap.  I have had many problems with this over the years with mine dong exactly the same thing.

Alright, Jeff. You may be right, buddy. If it shakes out that way, I concede defeat.     

UPDATE:

I got as far as pulling the front drive shaft earlier this afternoon (to see if the vibration/shudder remained with the front drive shaft removed). The vibration was still there during the test drive with no front drive shaft.
I had a friend over that was going to help me with the jack stand test (jack stands under axles, run through all gears). Unfortunately, he left his phone in the driveway next to my rear wheel and I rolled over his phone after I pulled the front drive shaft.      Believe it or not, my Zuk only killed his screen. He could still make calls and receive them.

While next to the Zuk, he noticed there was some movement when I put it in gear. He got behind the wheel so I could see, and this could very well be the problem. The pinion moves quite a bit when you release the clutch.     Looks like axle wrap just moved up a few notches on the "Primary Cause" list. Actually, it seems that the axle wrap allows the pinion to move a bit too far upward, so I guess axle wrap AND pinion angle are looking to be strong contenders here.

Anyway, I got this friend that turned loose of a bunch of stock Zuk axle stuff when he moved on to bigger, better axles. (Thanks, my friend)
I went searching for the stuff in the garage. I had stashed it for such an occasion, if the occasion ever occurred. In the box o'booty I'd received were had two sets of shims (3 degree shims and 5 degree shims). I also borrowed an angle finder from a friend earlier this evening. I'll be checking the rear pinion angle and the rear output flange angle for the difference when things calm down in a little bit. (Our kids have friends over.)

In addition, I believe I'll be adding a lower Samurai front spring leaf to each front CJ (in the rear) to stiffen these springs a bit. I know the ride will be stiffer, but I'm hoping this will be adequate.

[loveofjazz]

UPDATE:
Found a lull in the kid storm. Rolled around underneath the Zuk with a flashlight and the borrowed angle finder. Seems like the transfer case angle is at 2 degrees, and the rear pinion angle sits at 5 or 6 degrees.

I'm thinking that I should try the 5 degree shims on this. Any thoughts?

[Freebird01]

use the 3 deg shims jim... if you got wrap like you say you will want that pinnion a hair low

[loveofjazz]

use the 3 deg shims jim... if you got wrap like you say you will want that pinnion a hair low

The rear pinion angle is 5 or 6 degrees and it's higher than the 2 degrees on the transfer case rear output flange.

[Freebird01]

ok i was misunderstanding him. after a phone call i recommend going with the 5 deg shim.

[Bama Zuk]

YEP The jack stand trick is a good one to see what is going on while keeping the rig still.

[loveofjazz]

YEP The jack stand trick is a good one to see what is going on while keeping the rig still.

Never got to the jack stand test. We caught the axle wrap issue with all 4 tires flat on the ground.
I'll give that a shot soon enough.

[viking]

My T-case was wobbling in first and second gear, I pulled the driveshafts and the U-joints were good.  Could be spring wrap because I changed out the springs for newer ones with Teflon hockey pucks  isolating the ends of each spring leaf under the main leafs.  Could also be too soft of T-case mounts so I went to some local tire dealers and got heavy duty shock end rubber and poly mounts, drilled out the frame mount holes to 5/8" to clear the end sleeve  and bought three 3/8" X 2 1/2" #8 hard bolts and double nutted them so they wouldn't come loose.  I had to use two poly mounts to get the spacing of the OEM mounts.  There is a little more noise, probably because the poly mounts are a lot stiffer than rubber and I may change the top one with a rubber mount just to see if it makes it quieter.

[viking]

P.S. T-case doesn't wobble anymore.