Can Not figure out this @%#$@ Vibration!

[Tug-n-pull]

1067870

Ok here is the deal 87 YJ 4 banger 5 speed! Devloped a fine fast vibration at about 50 MPH diffently a drive line thing. Changed out the read Universal Joints and no help. Droped the front drive line and drove it up to 75 MPH no vibrations all nice and smooth! ok I put new u joints up front and put it all back on there and bang the vibrations are back again. I can not see any missing balance weights anywhere or any damage but something has gone wacky in the shaft between the transfercase and the front differential. any thoughts out there my Jeeper Friends? Thanks in advance for any help Tug :-? [addsig]

 

[MudderChuck]

1067880

I had a rear drive shaft, that was severly rusted, messed with the balance. I had a front double carden joint in my Dodge (probably the same one in a Jeep) that had a spring in between the two U-joints by the tranfer(kind of a tensioner), when the spring broke (wore out) it developed a vibration.
I really can´t remember wether the 87 4 banger had the carden joint or the CV type joint. I´ve never really thought about it much, but shouldn´t the shift motor for the front axle, pretty much make the front driveshaft an appendage rather than a rotatiing functioning part? Does your 4X indicator light, light up? Maybe the front axle isn´t disengauging.
Put her in low gear and give her some gas, pretty heavy duty acceleration, does your transfer chain make a ratcheting sound? I´ve picked up a vibration, from loose tranfer chains, but never in a 231.
Eye ball your front axle U-joints real good, like flashlight and magnifying glass. Any movement at all, around the rubber seal for the bearing caps, means time for a change.
Fronts rarley mess up, but on numerous occasions, the carrier bearing in the diff. grow a little to much play. If you take the front diff cover off, try prying up and down on the carrier group. Shouldn´t be any more than minimal play in the carrier (like a few thousanths). Better to get new bearings in there, before things start to wear funny.
Out of ideas Tug.[addsig]

 

[Tug-n-pull]

1067888

Does your 4X indicator light, light up?

Well that may be it cause the light does not come on when I shift the dang thing in to 4 lo or hi. Guess it is time to look into the vaccum lines and the up front heh! Thanks Tug[addsig]

 

[RayOvac]

1067923

Yeah tug your shift motor may have stuck...leaving your axle in the "engaged" postion. Best way to check that is to drive very slow and have someone look under the jeep and see if you front driveshaft rotates. I would be that the shift motor got stuck and that is causing your prob. The front driveshaft on a YJ normally does not rotate when not in 4wd so it has no balance weights on it. It is a single cardon shaft as well.

The TJs have a double cardon (CV) joint on the front. They have no shift motor so it is engaged all the time.

[addsig]

 

[Tug-n-pull]

1068076

What is the best way to unstuck the dirty little devil! Remember I am not all that Mechanicaly inclined. But i can talk fast, hehehehehe Any advice is going to be so appreciated. Tug[addsig]

 

[RayOvac]

1068088

Well tug worst case scenario is the shift motor is kaput. You will have to either

A) screw it and get your front driveshaft balanced...always engaged front no vibes

B) head on down to the $tealership and order a new shift motor $$$

C) buy a posi-lock $$$

D) make your own posi-lock

Here's the LINK to a guys page that did just that.

I would check all the [EDIT]vacuum[/EDIT] lines extensivly before assuming the shift motor is bad...but they are known to fail when they get old.

edited by: RayOvac, May 15, 2003 - 10:51 PM[addsig]

 

[Tug-n-pull]

1068109

Thanks Rayovac, you have pulled me out of so many ditchs and bogs. Glad you are on the trail. Tug[addsig]

 

[rockwrangler]

1068119

you might also check into manual locking hubs. Warren has a sweet set up with "hub fuses" They are pretty slick, they create a weak link that is easily replaced if broken on the trail. You can select different size fuses to match you running gear. They are designed to break before you snap an axel or a ujoint. This is still pretty expensive, just thought I would give you one more option.[addsig]

 

[Tug-n-pull]

1068353

Thanks again to all that gave advise here. Mudder Chuck you lead me into the light on this one Thanks. Today I went to the bicycle shop and bought the items needed to convert to a home made Posi lock system. Ray your link and advice on the posi lock was the ticket i just printed a copy of the page and walked through it like a seasoned ol wrench. I took it a couple of steps farther and drilled and taped the hole in the houseing where the cable goes in and sealed the vacuum holes with blue gasket silicon. It works like a dream and to have 2 wheel lo range is awsome. Tomorow I shall add a thumb throttle and spend the rest of the day playing in the woods. On the way to the woods there will be no vibrations in the drive line. I am so simple when it come to mechinal stuff and I was able to do this home made mod, so anyone can do the same. and had a ball doing it. Later on down the trail Tug Peace out :-D

edited by: Tug-n-pull, May 17, 2003 - 05:14 PM[addsig]