Driveline Vibrations

[pdw]

Does anybody know of a simple way to confirm that the rear transfer case output is lined up with the pinion on the rear axle?

I have a Currie 9" high-pinion rear axle and a 33 Engineering transfer case skid plate. Since I added the skid plate I am experiencing driveline vibration at differant speed and differant gears--5th gear being the worst.
I am wondering if I need to adjust the transmission mounting holes on the skid plate to the left or right???

I have a SYE kit and a Tom Woods driveshaft that I installed about two years ago, so I dont think that is part of the issue.

Any help would be appreciated.

[Jason]

I used an angle finder I bought at Harbor Frieght when I need to set the axle angle. Cost about 10 bucks.

[pdw]

I used an angle finder I bought at Harbor Frieght when I need to set the axle angle. Cost about 10 bucks.

No, not an angle finder-although that might be helpful in other areas. But, I would like to know if anybody has had any issues with the transfer case output being lined up with the pinion.

When I lay under the rear axle of the Jeep and look up at the driveshaft, the driveshaft looks to be at an angle-horizontally. What I am trying to describe is the transfer case appears to be pointing off towards the right rear tire.

Does that make any more sense??

[ECV Jeep]

If the rear axle is pointed away from the pinion, that is the likely culprit to your vibration problem. Having a slight angle on the front drive shaft is acceptable, but I would not want this on the rear. If the t-case has moved in relation to the rear sine the new skid plate, I would imagine that you are putting undo stress on the driveline. I would make every effort to square things back up on your driveline.

[Jason]

No, not an angle finder-although that might be helpful in other areas. But, I would like to know if anybody has had any issues with the transfer case output being lined up with the pinion.

When I lay under the rear axle of the Jeep and look up at the driveshaft, the driveshaft looks to be at an angle-horizontally. What I am trying to describe is the transfer case appears to be pointing off towards the right rear tire.

Does that make any more sense??

Yes it does. I understand now. Different angle. I was thinking up and down.

[pdw]

If the rear axle is pointed away from the pinion, that is the likely culprit to your vibration problem. Having a slight angle on the front drive shaft is acceptable, but I would not want this on the rear. If the t-case has moved in relation to the rear sine the new skid plate, I would imagine that you are putting undo stress on the driveline. I would make every effort to square things back up on your driveline.

OK you guys understand what I am trying to describe!

So, has anybody heard or used a simple method to determine the horizontal angle (left, right or straight) of the drive shaft? Would a straight edge held against the back end of the transfer case do the trick? Anything like that to suggest?

[Kodiak Spirit]

I would use the trusty tape measure and roofers square to get a good center measurement of the rear diff and than make the t-case match... or you could just square the jeep up next to a wall and measure off of that... I dunno...

[pdw]

I would use the trusty tape measure and roofers square to get a good center measurement of the rear diff and than make the t-case match... or you could just square the jeep up next to a wall and measure off of that... I dunno...

I think that I'll try the tape measure and roofers square idea, thanks.
I wouldn't trust the walls in my house for measuring anything! They bend and wave-things sure were built differant back in 1976!

[Black & Tan TJ]

You could also try a piece of string/rope from the center of the pinion yoke to the center of the CV joint or output yoke if you can.

B&T TJ

[pdw]

A simple fix & a happy ending!! :yay:

The 33 Engineering skid plate that I purchased did in fact have some engineering built into it! The six bolt holes for mounting the transfer case skid to the frame were slotted and allow for side to side adjustment.
So, I started by loosening the six mounting bolts along with the bolts on the transmission mount. Then I placed a bottle jack between the frame and the transmission. As I slowly extended the jack, I could see the amount of horizontal angle being reduced on the driveshaft. To make certain that I wasn't simply bending the transmission mount around I introduced my 5lb sledge and plastic mallet to the passenger side of my skid plate. After a couple of quick whacks (with the plastic mallet serving as the go-between for the skid plate and the 5lb sledge) and I am almost completely vibration free!

[ECV Jeep]

Glad to hear it worked out okay.........I just wish all fixes were that easy!

[mrthieba]

Sometimes the BFH is the best tool in the box.