Front transfer case yoke runout

jeepndogs

TJ Enthusiast
Joined
Mar 5, 2017
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653
Location
Crete, IL, United States
Little bit of a back story here. 04 LJ,Zone 3 in lift, 33's, 4:88 gears, all 8 adjustable arms, adjustable track bars front and rear, rebuilt transfer case, front and rear axels completely rebuilt, SYI, its basically a brand new jeep with the exception of the motor.

I have "THE VIBRATION" harmonic above 69 mph. Pull the front shaft and it is gone. I have replaced the front shaft with a rebuilt stock, two Tom Wood's and I currently have a Denny's drive line shaft in it. This shaft has been the best, the front pinion is .5 above the driveshaft, I have tried it in a million different angles and no change.

I put the jeep up on stands yesterday and ran it in 4x4 at idle and I can see that the front shaft has a decent amount of runout at the end that attaches to the transfer case. The shaft was high speed balanced so I can't believe it's the shaft. I am thinking the front yoke onbthe transfer case has excessive runout?

Has anyone experienced this? The jeep was bone stock when I bought it and has absolutely no sign it ever left the pavement.
 
Have you verified the big nut that holds the yoke on the pinion shaft on is on tight? I've seen more than one front end vibration caused by a loose yoke nut.
 
Case? As in transfer case? I was referring to the axle's pinion nut.


Yes the transfer case yoke is tight and also the front pinion nut is tight. I can visibly see at least 1/8 or more runout in the front driveshaft about 3 in below the cardan joint. I pulled the shaft and put in a different shaft to compare and the runout is still the same.
 
Yes the transfer case yoke is tight and also the front pinion nut is tight. I can visibly see at least 1/8 or more runout in the front driveshaft about 3 in below the cardan joint. I pulled the shaft and put in a different shaft to compare and the runout is still the same.
Sounds like you figured it out, a bent tcase input shaft.
 
The center of the yoke looks to be spinning true. I'm wondering if the locating tabs are damaged?
It could be the u-joint is not properly positioned between the locating tabs inside the yoke. They serve to insure the u-joint is properly centered and seated all the way down into the yoke. I had that problem once after installing a new driveshaft, it caused a vibration that took me a week to find that is what caused it..
 
It could be the u-joint is not properly positioned between the locating tabs inside the yoke. They serve to insure the u-joint is properly centered and seated all the way down into the yoke. I had that problem once after installing a new driveshaft, it caused a vibration that took me a week to find that is what caused it..


I'm going to try replacing the yoke, the shaft is fully seated between the tabs right now. But like I said I can see the shaft moving and I swapped shafts and it did the same thing. I thought I seen something in another post someone found out the factory yoke was machined a little off center.

I had some vibes from the front with the 3:73 gears, they didn't start till about 70 though. With the 4:88's it's coming on at about 60.
 
I think you misunderstood me, I said to make sure the u-joint (!) was centered in between the centering tabs inside the yoke where it seats under the straps that hold it in.
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I understand what you were saying. The axel side of the driveshaft does not have any runout, the cardan side of the driveshaft is the side I have a lot of runout on. That side has no straps that attach the ujoint to the yoke of the transfer case. I have checked the ujoints at both ends of the shaft and they are both fully seated between the tabs in both the pinion yoke as well as the transfer case yoke.
 
Trying to learn something here. What is runout? What do you see the driveshaft doing?
out

Runout is when something is spinning out of its axis. Basically I can see the driveshaft wobble so to speak even at an idle speed. If I were to take a fixed object and slowly bring it into contact with the driveshaft it would only make contact with a small portion of the shaft. If I wanted to get an exact measurement I would use a dial indicator to measure the movement so to speak. Since I can see it just by looking at it I know it's somewhat excessive
 
out

Runout is when something is spinning out of its axis. Basically I can see the driveshaft wobble so to speak even at an idle speed. If I were to take a fixed object and slowly bring it into contact with the driveshaft it would only make contact with a small portion of the shaft. If I wanted to get an exact measurement I would use a dial indicator to measure the movement so to speak. Since I can see it just by looking at it I know it's somewhat excessive
I know this is an old thread, but did you ever solve your vibration issue? I am currently trying to track one down as well. Starts at 70 MPH and so far I've been through 2 Tom Woods shafts and am currently having my old Adams rebalance after getting rebuilt. No vibrations with the front shaft removed, Pinion is .5 higher than driveshaft. The Adams driveshaft didn't have any vibration before, but the cv went out, which is when I tried Tom Woods.
 
Yes, I fixed it but I sold it last year. I finally ended up just doing a Yukon locking hub kit, when the hubs were unlocked the front shaft didn’t spin. Problem solved but it also cost me $3000
 
Yes, I fixed it but I sold it last year. I finally ended up just doing a Yukon locking hub kit, when the hubs were unlocked the front shaft didn’t spin. Problem solved but it also cost me $3000
Seems like that's everyone fix. Looks like i may have to deal with the vibe cus that's out of the question.
 
I spent a ton of money and probably close to 6 months trying to fix it. Finally did the hubs and never looked back. Probably put 20k mikes on it after that and never had any issues.
 
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Yeah, I didn't have a vibration but then I swapped my control arms to Savvy arms and installed a Tom woods shaft at the same time. Been through 2 Tom woods shafts now, actually shipped the second one back today. My vibration free shaft was a Adams off-road shaft, but the CV started squeaking, which is why I replaced it. This past weekend I greased the CV in the Adams, installed it and didn't have any vibrations again. I had a local driveline shop (Quigley 4x4) replace the CV and all the ujoints yesterday in it. Installed and the vibration is there but not like it was with the Tom Woods shafts. I am dropping it back off this evening and they are going to rebalance it tomorrow. Hoping that solves my problem.