Death Wobble. Parts tight. New trackbar. Loose steering box??
 

1999 XJ Sport 4.0. 255K miles, 231. Started getting slight death wobble last year at speed but went away on its own. No need to stop. Was slightly present last week, but installed a new IRO 2 inch lift. New coils (200LB HD), and full length add-a-leaf for rears. Also new Monroe shocks in all 4 corners and new trackbar. TERRIBLE DW at 55-60 if hitting a highway seam or bump. Broke mechanical fan shroud from fan hitting it when shaking started at 65MPH. yay

Eyeballing the whole shebang from underneath while a buddy turns the wheel, everything looks and feels tight now with the new trackbar. Ball joints check out fine when jacked up and using a 4 foot bar to move wheels up/down. No play in the ball joints or tie rod ends that I can see/feel.

Here's where it gets interesting... When both front wheels are off the ground and XJ supported at the front axle, steering locked. I can move the tires left/right about 1/2 inch or so. They both move at the same speed/distance. Everything seems tight this way, BUT the pitman arm/shaft moves before the input shaft to the steering wheel moves. I'd say about 1/4 inch rotation of the output shaft before the INPUT shaft starts moving at all.

There is about 2 inches at least of "play" in the steering wheel and the XJ does seem to "wander" a bit.

Is my steering box shot? I'm assuming this "play" at the output shaft would cause death-wobble? Or at least contribute to 90% of it once it starts?

I will try adjusting the box tonight when I get home I guess.

UPDATE:
THIS little guy was about 90% of the problem. I picked up a nice low-mileage steering box from a salvage yard yesterday. I do NOT EVER want to replace that again. Although with the new lines, it should be easier than the rusty lines.. Anywho, no more wandering, bump-steer or that strange "rebound" feeling on small bumps. Its tight as a drum now.


https://cimg1.ibsrv.net/gimg/www.che...d5af945876.jpg

You can adjust it and see if that helps. How is your castor angle after the lift. Should be -5°

I just had a DW event and tightened up the adjustment screw a little. I now have maybe an inch of play.

That said, proper steering box adjustment is a 3 page document requiring Spanner Wrench C-4381, high and low torque wrenches and pulling and draining the box to work on the bench.

I have read that tightening the screw too much will result in rapid wear of components.

FWIW.

Yeah.. I know that messing with the box will probably shorten its life or even cause complete failure. Im planning on replacing it anyway. Just looking for the best price/performance. Leery about a reman from the local parts places, but then again, why spend $1100 for a new one on a 22 year old Jeep with 255K..

Correct^^. Over the years I've adjusted them I reckon you could say by trial and error. I tighten the adjuster NO MORE than 1/8th of a turn at a time. Then check for results. You do not want it to get to the point where the steering wheel doesn't return to it's normal position when it's let go.

What's the track bar/drag link angle look like? What kind of steering stabilizer you got?

I hope adjusting it 1/8 of a turn at a time gives some improvement.

Remans are hit or miss. The RedHead boxes have done well for some people.
Or, you might just try a box from the JY, which is what is on my Jeep for several
years now.

When you got the new track bar , was it longer? Or adjustable...you need one of those options with a lift. Your sway bar end links are also probably way out of whack

Angles look ok. Its sitting at 19.5 in the front from 17.5 inches. I picked up a new KYB stabillizer but Im waiting to install that until I get my DW fixed.

This is the point where I think we need to see some pics of your front end parts

What's in there now? An old one or nothing?

DW is an inherent problem with straight-axle vehicles. It can even occur with brand new vehicles. Mopar admits it:

https://static.nhtsa.gov/odi/tsbs/20...69208-9999.pdf

A few rants:

https://www.cherokeeforum.com/f2/ste...ilizer-263028/

A bunch of Dodge Rams have the same problem:

https://www.drivingline.com/articles...ses-and-cures/

https://thelemonfirm.com/2019/12/24/...obble-defects/

Steering stabilizer is a critical part of preventing harmonic resonance (DW). It's like the finger touching a vibrating tuning fork.

Again, I've been in vehicles that broke tie rod ends and ball joints, and it can be exciting (up to the point of becoming terrifying, anyway) but after due diligence given to all steering components (including control arm bushings), it may be that the steering stabilizer is the cure rather than the band-aid.

When is the last time you changed the front axle U-Joints? My case of DW at 55-60 mph was cured by their replacement.

Just something to look into.

Did you mean +5*?

my bad, dyslexic that day

I tightened the steering box last night. Really helped with the steering-play. I think I will be ordering a new box today. Im shotgunning the front end with parts. Parts will all be here by Friday. Timken hubs, new GC LCAs. Today is all new Moog rod ends, bars, ball joints, etc. I replaced the outer U-Joints about 2 years ago and those are still tight. I replaced the inner oil seals a few weekends ago so I had the entire axle torn apart already. I figure 22 years and 255K miles has been a great run for all the parts so why not replace everything and get an alignment. Weekend project for now. I think my major problem is/was the steering box play at this point.