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Discussion Starter · #1 ·
With the 4" lift on a Tj could it be my drive shaft? Do I need a slip yoke shaft or is there another solution? It only happens at 70-80km/h. It can't be good over an extended length of time.
 

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could be a u joint could be your tire balance

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This 4x4 thing is starting to take away from my beer fund.
 

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Superfly
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Originally posted by 4Lo:
With the 4" lift on a Tj could it be my drive shaft? Do I need a slip yoke shaft or is there another solution? It only happens at 70-80km/h. It can't be good over an extended length of time.
Yeah, it _could_ be your driveshaft. Have you measured the pinion and tcase output angles to see if they're parallel?

Did you have this vibration when you first lifted your TJ? Or did it happen a while after the lift was installed? Has anything on your vehicle changed just prior to the vibration appearing?


...lars

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19911995409993004:144444.103512.58274

[This message has been edited by lars (edited January 07, 2002).]



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Hello 4Lo,
I have the identical happen as you do on my vehicle,after i have installed the lift up kit on my car. The annoy nosie suppose to be coming out from the drive shift.The mechanic tell me that it is acceptable,but i am reluctant this reason because I have no choice on it.Incidentally, the U-joint or slip yoke will be warm out faster then usual because it does conflcit with the drive shift whenever it spin.For instance, my case is worse than you because the drive shift uses to hit the muffler when the drive shift move to left.

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Fat Mike
94 Silly sidekick with 3" calmini suspension lift >.<
 

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Discussion Starter · #6 ·
???Good I am not the only one???

The vibration started about a month after the install of my lift.I am running an unbalanced tire on the front right but the vibes seem to be coming from the rear of the vehicle. It seems like the drive shaft. I have greasable u-joints and they have been greased. It is probably u-joint wear but I just thought I would get a second opinion first.
 

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Discussion Starter · #7 ·
How do I measure pinion and t-case output angles..do I need a specialty tool for this?

Is the pinion angle the driveshaft input to the diff?
 

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Superfly
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Originally posted by 4Lo:
How do I measure pinion and t-case output angles..do I need a specialty tool for this?

Is the pinion angle the driveshaft input to the diff?
You need an angle finder. Here's a photo of one:


You can buy a decent one from Home Depot or most other hardware stores for around $25. Get the most sensitive one you can find.

Yes, the pinion angle is the driveshaft to the diff angle. That's a tough one to measure. I usually put a piece of flat steel against the diff housing collar (the part through which the pinion shaft protrudes) and measure the angle off of that. The pinion shaft angle will be perpendicular to that measured angle. Know what I mean?

BTW, if you only noticed this vibration a month after your lift, there are two likely causes:
1) U-joint wear. You can't really eliminate this possibility without removing the driveshaft and inspecting the u-joint.
2) Your springs settled which resulted in the pinion angles no longer being correct (because the lift height has changed). If you have adjustable length lower control arms, this should be an easy thing to fix.

BTW, if you know one of your tires is out of balance, you should get it fixed right away.


...lars

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19911995409993004:144444.103512.58274


[This message has been edited by lars (edited January 09, 2002).]



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Discussion Starter · #9 ·
I found the problem. The bolts holding the rear trac bar had come loose and finally just fell right out, leaving it hanging. I've replaced the bolts but I still need to modify further so it does not happen again. This is the second time the bolts have loosened up so I think I have an idea.

If I replace the stainless bolt with a stronger steel bolt thread onto it a castleated nut drill a hole through the threaded part of the bolt just aft the nut and install a cotter pin...would this stop it from vibrating loose in the future?
 
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