Bad Vibration

Jeffrey92r

Member
Joined
Feb 13, 2011
Location
Wake Forest
I have never had this vibrating problem untill i got a rough country 4 inch lift on my yj. I talked to some people and some say its because my drive shaft. Some say that i should get a slip yoke eliminator and it will cut the vibration out. Others have said that getting a slip yoke eliminator would help a little but won't do much. I dont want to spend 500 dollars to find out that it would cure a little vibration. Also, Could it be possible that its my rear differential? I changed the oil in it today and it seems to have cut some vibration down and when i changed it i noticed my spider gears seem to be in some rough shape. they have nicks in it and some look jagged. when i changed the oil i noticed that i could take about three pinches of chewed up metal out of the old gear oil which does not seem good at all. another problem is that i keep on breaking my u-joints mainly the one that connects the rear driveshaft to the transfer case. i prob. changed that one about 4 times in one year. Whould this mean that my transfer case is going bad? If anyone can help me out, it would be great
(if someone lives near the Wake Forest area and would like to go for a test drive i would really appreciate it)
 
Did the RC lift springs come with wedges built in to adjust the pinion angle? Its possible you may have installed them backwards, adjusting the pinion down instead of up.

The metal in the diff is not good though. How do the teeth look on the ring and pinion? To check the pinion you might be able to sneak a mirror over the carrier and see it, but for a good view I'd pull the carrier.
 
Normally the kit will come with a 1 inch Tcase drop as well. Like said above, make sure the rear pinion is pointing up a little towards the tcase.
 
When does the vibration occur, is it worse at steady speeds or at take off? Hop under it and take some pictures for us. It does sound like your pinion angle is off though. A 4" lift should be "okay" without the SYE and a CV shaft, even more so if you used the shims and tcase drop.

As for the metal shavings, you got probs there. Sounds like you need new spiders. Inspect the ring and pinion as suggested. This could also be creating some vibration, but is more likely to just make noise.
 
i did install the 1 inch t-case drop. also the ring and pinion looked to be fine its just the spider gears for some reason there was no scorns on the ring and pinion though. ill try to get some pics to help.
 
the vibration usualy starts when i hit about 50 mph i know its not my 5th gear because it will still do the same thing in 4th and 3rd. also when i have it in neutral it will still do it. Once i hit around 45 the vibration stops. sometimes when i go about 65-70 and then reduce speed around 50-55, the vibration will sometimes stop. also this vibration is not really in the steering wheel it does not have death wabble or anything. it just vibrates the body and you can feel it at most in your seat and in the floor. you can feel it at most if you where to sit in the back seat.
 
Spider gears will not cause a vibration while driving straight due to the fact they are staionary if both tires are rotating at the same rate. The last thing you did was put in a lift when the vibration started and seeing that you did install the T-case drop I would pull the rear shaft and check for a binding U-joint that was ran at less of an angle for so long and you have increased that amount of rotation that it is now doing. If you dont feel any tight spots then the slip yoke eliminator would prob be the next step.
 
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