Finally Lifted now have a vibration when Accelerating Only

RED_KJ_666 · **Posted:** Sat Mar 13, 2010 8:36 pm

It has a slight whump-whump-whump when Accelerating from a stop that came along with a vibration that matches the noise. Its also really noticeable anytime under 20km/h other than that its not there at all. My front Drive shaft is Brand-New. I'm thinking CV maybe? The weird part is that my KJ was so Sagged it looked like a Reverse Lift CV's where coming out of the Front end and stepping up to the Hub Unit. Where They now Step Down and into the hubs at the Same Angle as before So the Angle on them has pretty much not Changed. I'm Confused really. anyway to check CVs without Removing them?

riptricket · **Posted:** Sat Mar 13, 2010 8:58 pm

did you have an alignment performed?

Zack A · **Posted:** Sat Mar 13, 2010 8:58 pm

Check U-Joints also

RED_KJ_666 · **Posted:** Sat Mar 13, 2010 9:06 pm

Yeah I had it lined up. It is spot on now. I also checked my U-Joints on the rear D-Shaft they are fine. That was my first thought. I also had the Tires Re-Balanced

qwert380 · **Joined:** Mon Jan 04, 2010 11:11 pm **Posts:** 98

i am not sure what the vibration dampener is but i know that some have removed after lifting their KJ

RED_KJ_666 · **Posted:** Sat Mar 13, 2010 9:32 pm

The Vibration Dampner is the Big block of Plastic that hang off the front of the Rearend Housing. I haven't removed it. The Vibration and Noise are definetley in the Frot.

tommudd · **Posted:** Sat Mar 13, 2010 9:50 pm

How did you check the rear u joints?
They can feel tight but be rusted solid almost!
Thats my first guess

Big block of plastic hanging off the rear housing??????

RED_KJ_666 · **Posted:** Sat Mar 13, 2010 9:53 pm

Thats what it looks like to me Tomm. Maybe its not lol? It's still on there tho. You really think it is my Rear D-Shaft tho because it was not there at all until I lifted it. I even have double checked all the bolts triple checked the Clevis bolts.

JeepinJarhead03 · **Posted:** Sun Mar 14, 2010 2:05 am

big block of rusty pot metal that looks like a freaked out coffee can maybe

i'd place bets on the u-joints

that's what mine turned out to be

Boiler · **Posted:** Sun Mar 14, 2010 4:16 am

RED_KJ_666 wrote:

Thats what it looks like to me Tomm. Maybe its not lol? It's still on there tho. You really think it is my Rear D-Shaft tho because it was not there at all until I lifted it. I even have double checked all the bolts triple checked the Clevis bolts.

Rear drive shaft angle is greatly affected when it's lifted, just like the CV's. I got a vibration when I lifted mine that I've pretended wasn't there for the last few months. I had it in the shop to mount some tires recently and I was told I had a bad U-joint. I haven't done anything with it, figured I'd ask soon what exactly to look for and what do replace.

I know when I added weight to the rear, compressing my springs about 3/4", the vibration got noticably softer.

KJ in CO · **Joined:** Thu Apr 09, 2009 4:06 pm **Posts:** 346

Its always so hard to diagnose these things. I dont know if it would be the drive shaft if it is only happening when you are starting to accelerate from a stop and arent moving that fast yet. I would say that it could be a one of the wheel bearings are going bad. Does it sound like a roaring sounfd at all? Maybe, that is my :2cents:

, being that I had the same issue

jimymc · **Joined:** Thu Dec 17, 2009 7:51 pm **Posts:** 248

I had something quite similar. I could hear it at slow speed, but it would really roar from 60mph on up. Turned out to be the CV and intemetiate shaft on the passenger side. The local Chrysler/Jeep dealership ran the car up enough on a lift to get the wheels off the ground, put it in 4WD and you could see the half axle thumping around inside the CV at idle. When they finally got it out the half axle and intermediate shaft were rusted together. They had to drive the intermediate shaft out from the other side. If you can get hold of the use of a lift to get all wheels off the ground you might want to try it to see if you can see the same thing. Just an idea. Beats tearing everything down to take a look. Of course, you will want to remove the front skid plate to get a good look.

tjkj2002 · **Posted:** Sun Mar 14, 2010 7:43 pm

Like stated sounds like bad u-joi9nts in the rear driveshaft.When you change the angle of the rear driveshaft(from lifting) you will always wearout u-joints faster,that is a fact even if they are greaseable u-joints.

jimymc · **Joined:** Thu Dec 17, 2009 7:51 pm **Posts:** 248

Have you found out what it was? Just curious.

RED_KJ_666 · **Posted:** Wed Mar 24, 2010 9:35 pm

It's a CV shaft. Driver Side Front.... being replaced soon

jimymc · **Joined:** Thu Dec 17, 2009 7:51 pm **Posts:** 248

Sorry you have the problem, but I'm sure you are glad to have it diagnosed and will be happy to have your Jeep back in good working order. :JEEPIN:

RED_KJ_666 · **Posted:** Sun Apr 04, 2010 7:17 pm

So it turns out that the shop that replaced my Wheel bearing only put 2 bolts back in it, put it in crooked. I should have checked closely sooner but figured if thats where the sound was coming from then thats what it would be CV shaft. WRONG.... 2 Days ago the Vibration just stopped and I thought Hey Bonus.... Now I have a spare CV shaft to go with the rest of my parts. Then yesterday I was towing a 95 YJ Sahara home and on the way to get it the ABS light came on but went away after I had the YJ loaded on the way home we where following an old clunker car and could smell hot rubber but wrote it off as that old car. Then This morning I did a walk around before wheeling and noticed that both tires ruined on the edges one on the inside one on the outside, They where fine before I towed the YJ I always do a walk around before towing. I think the Bearing was wedged in crooked with the 2 bolts and it finally popped into its spot causing my alignment to go way off. Both other bolts are loose as well as the Axle nut. The same shop actually left my D-Side wheel loose after the work as well only torquing one nut. My ABS light is also now permanently on.. So the Tally is 2 tires, a CV that has a groove, wheel bearing, and possibly a Knuckle. I will update tomorrow when I go back to the Shop possibly with a Lawyer.

Boiler · **Posted:** Fri Apr 09, 2010 1:10 am

Ouch, really sorry to hear about all your problems with this.

I replaced my U joints a couple weeks ago and it did take away my roaring. I still have the vibration on accelleration, so now I guess I take a look at the front. This scares me a little...