Death Wobble/Uncontrollable Shaking in TJ????

[redcheetah]

I have a 1997 TJ (2.5L manual) with about 5" lift (RE), 36" tires, lockers, etc. and a leaf spring conversion in the rear done by the PO.

When driving I will occasionally hit a bump in the road, think RR tracks or separation in the freeway, and the Jeep will begin to shake mildly and then work itself into such a furious shake that I have to skid to a halt before I lose control and end up off the road. It almost always seems to begin when the rear axle goes over the bump. It has become consistent and I can only trailer the Jeep now. I would like to figure this problem out obviously so I can drive the Jeep. The Jeep will also do it on fire roads on the way to the trail which makes for a rather exciting trip:eek: .

Many people have told me this is death wobble but castor, camber, alignment, suspension setup, etc has all been checked and is in order.

The Jeep has 36" Super Swampers on it now (bias ply). The last resort a few people have told me is to check the tires to see if one is horribly out of balance/round and is throwing the entire Jeep out of balance when it hits bumps once in a while.

The Jeep does have a leaf spring conversion in the rear done by the PO. I do not run the track bar on it and I don't think it matters but just though I would throw that in in case I am wrong, which is often.

I would like any opinions as to what this may be caused by or areas to look into.

Thanks

[mUD uCKeR]

Trying playing with the air pressure in your tires... I did this... and although for me it didn't fix it... it helped lots. I have no idea why... But for me ... it kinda worked.

[redcheetah]

thanks for the idea - anyone else have any ideas or opinions?

Thanks

[nasvik]

Toe-in. Bend a tie-rod recently?

Paul

[Tech Tim]

snip....Many people have told me this is death wobble but castor, camber, alignment, suspension setup, etc has all been checked and is in order.......

Post up the specs of the camber, caster etc...most death wobble problems is due to front end alignment, especially caster. Many shops will tell you it's all in order, but is way off.

We've had our TJ checked by 3 different shops in the last couple months and only one shop was able to to give us accurate readings. They didn't have the right parts to fix it, but at least they could give us a complete accurate print out.

[rock5150]

Mine did the same thing, it was a worn out tracbar. Also check for worn steering
joints, loose steering box, etc.. any type of play could cause it.

[bnine]

Many people have told me this is death wobble but castor, camber, alignment, suspension setup, etc has all been checked and is in order.


I've treid to fix DW with alignment time after time and it has only ever worked once when I had way to much toe. It was also a very tempory fix, it just helped the worn out part that was causing the DW run a little more stable until it was totally shot.


The Jeep has 36" Super Swampers on it now (bias ply). The last resort a few people have told me is to check the tires to see if one is horribly out of balance/round and is throwing the entire Jeep out of balance when it hits bumps once in a while.


Tires should not cause your DW. Tires are the absolutely last place I would look.


The Jeep does have a leaf spring conversion in the rear done by the PO. I do not run the track bar on it and I don't think it matters but just though I would throw that in in case I am wrong, which is often.

I would like any opinions as to what this may be caused by or areas to look into.

Thanks

You're right, the rear should not be having an effect. The only thing that would possibly help contribute somewhat to it, is if your rear axle was so out of line that you had major dog tracking.

I just fixed another case of DW last night. And again it was the track bar. Thats about 6 this year I've fixed with track bar issues.

This time it was sneakier. TB felt tight, but when I removed it, the axle mount hole was ovaled out a bit, causing slop in the bolt.

Couple diagnostic tips for tracking DW.

Slow speed initiated. Definately worn part issue, slower the DW easier the part will be to find.

High speed. Over 60mph initiated, likely a worn part in early stage of wear, really hard to detect, Toe in fine adjustment can put it off until the part is dectctable.

Wandering and dead spot in the wheel that wasnt there previous to DW. Immediate track bar issue. Loose heim, blown bushing, loose axle bolt, rounded out lower bolt hole (pretty common, aftermarket tb's use 7/16's bushing sleeves, and we almost always bolt them in with the stock8mm bolt).

Progressively initiating at more frequent intervals, and slower speeds. Definately a bad or loose part. Check TRE's, balljoints, wheelbearings, steering box bolts, steering box slop, and control arm bushings.

Whatever you do, make sure you go over your parts with a fine tooth comb before blowing money on alignment adjustments and wheel balancing shit. By the sounds of your wobble, you will find it in a bad part.

Good luck.

[na83cj7]

My 93 Renegade was doing the same thing. After I hit a divider in the highway or pot hole at higher speeds it would shake so hard I thought the gauges were popping out of the dash. It was the ball joints. All four were shot. They were replaced and the hard shaking was gone.

[ZJeeper]

I just fixed another case of DW last night. And again it was the track bar. Thats about 6 this year I've fixed with track bar issues.
This time it was sneakier. TB felt tight, but when I removed it, the axle mount hole was ovaled out a bit, causing slop in the bolt.

X2 check the trac bar first. make sure all the bolts are tight and take them out and check for damage to the bushing/bolts/mounting holes.
the trac bar is what controls the horizontal movement of the axle and death wobble is horizontal movement of your axle at speed. i hope youre not this dumb but maybe your steering stabilizer is broken. mine broke on the trail one time and i had dw all the way home. new one fixed it

[mUD uCKeR]

I have 38.5" boggers... and when i rotated them... it created a DW situation. I have no idea why it would do this... I haven't tried putting them back.
I don't run a steering stabilizer.... haven't had a problem without one.
I jsut finished replacing the ball joints.
In the end... i figure it's the old rubber bushings in my waggy springs. They don't look very good. I will replace them and i bet it will fix the problem.
I Don't run a track bar.
I have been driving around liek that for about a year... no DW

[Tfritz]

X2 check the trac bar first. make sure all the bolts are tight and take them out and check for damage to the bushing/bolts/mounting holes.
the trac bar is what controls the horizontal movement of the axle and death wobble is horizontal movement of your axle at speed. i hope youre not this dumb but maybe your steering stabilizer is broken. mine broke on the trail one time and i had dw all the way home. new one fixed it

While I agree that the track bar could be the problem I don't think a bad steering stabilizer is. A steering stabilizer will just mask a bigger problem. I don't run a track bar or sway bar on my YJ and I have a 6.5" lift and 35's and have never had a problem. The best fix is to check all your bushings, bolts and the frame holes. If you don't find anything start replacing bushings untill you find the problem. It isn't a cheep fix but it's better than killing yourself or someone else.

[nasvik]

It's probably worth pointing out that TJ and YJ steering systems aren't designed the same. All good ideas, but...

I still say to check the toe-in. Good comment about ball joints, too.

Paul

[GaryTJ]

Death wobble is caused by the action of the ft axle moving side to side if it is not held solid in relation to the frame. Something has to start it. Tires o/round, and or out of balance. Too much scrub radius.

Regardless, if the axle is held solid, you have no death wobble, just an annoying vibration. Something has to be loose in order for death wobble to occur.

Have someone turn the steering wheel back and forth 3-4" and look under the vehicle for movement. Something is loose, you just have to find it. ANY movement in the track bar or mounts is too much.