Death Wobble on 2001 XLT SD 4X4 7.3L PSD
 

Hello. I have a 2001 XLT SD 4X4 7.3L PSD EXT Cab and started experiencing the death wobble a few months ago. My truck is stock suspension, and no lift or additional components. First happened around 55mph when I went across a rail road track. Last most people, I thought the wheel was coming off. It stopped after I slowed down. Now it seems almost any bump starts the wobble. I read this was common on most 05-08 models, but it not just exclusive to that model, or even Ford vehicles. I have probably read about 10-15 threads to educate myself before starting the troubleshooting and will need some experienced used to chime in. My 2001 has 338K on it. Below is what I plan to check/do based off my readings. Please let me know if some of this will not apply to my truck since it is an '01 4x4 and a lot of my findings were one 05-08 and even early 90s trucks. I'm not sure if all this hardware is on my setup based on my description of my truck above or if some of this terminology/parts are the same thing.

1) Check that the tires are inflated to the spec on the door sticker
2) Replace front shocks with Rancho RS9000XL or Bilstien's
3) Torque bolts on the Trac bar, replace Trac bar bushing and trac bar ball joint
4) Replace front wheel U-Joints
5) Replace upper and lower ball joints
6) Get an aftermarket Dual Stabilizer (Is this possible if truck is not lifted?)
7) Replace Panhard bar bushing
8) Replace Shackle bushings
9) Replace I-Beam bushings
10) Replace tie rods
11) Replace idler arms
12) Replace steering box
13) Replace Steering Damper
14) Check wheel, axle, suspension, i-beam brackets for cracks / loose hardware
15) Tire balance, alignment, get camber / caster & toe-in adjustment

I know that no one has really pin pointed the issue with the death wobble, but this seams to cover most everything. Where should I start? what shouldn't I do? What doesn't apply to my truck? Please help! Thanks!

I would start at the trac bar...9 out of 10 trucks I work on it was the trac bar bushing doing the death wobble...

You don't have I beams, nor anything related to I beams like I beam bushings, so you can cross all that off your list.

You don't need to touch the "front wheel U joints" to fix your wobbling issue. If what your are describing happens to you in 2WD with the front hubs unlocked, then the joint between the inner and outer axle shafts isn't even turning, so there is no correlation.

You don't have idler arms in your application.

The Panhard bar and the Trac bar are the same thing.

New shocks won't make any difference, but a steering stabilizer might dampen the bump steer you feel when your steer tire bumps a railroad track. But you don't need a dual steering stabilizer with stock tires.

The responder before me is right... look at your track bar. Don't just check torque, check to see if the thing is still there. Ok, I'm exaggerating... the bar doesn't go MIA, but the bracket on the axle on the passenger side quite often cracks. I saw one just yesterday parked on the side of the road. The trac bar was hanging by the steering stabilizer, because the track bar bracket had broken.

Cracks come before breaks, and when the road is smooth, nothing happens, but when a bump reverberates through the chassis, the crack can grow, or become dislodged (unlocked out of the grain structure of the fissure), which would literally add an unplanned flexible joint to your steering/suspension system.

Why not make the last thing on your list (#15) the second thing on your list? Take it to a competent alignment shop, and explain your problem. When the unit is on a rack, with a powerful flash light, look carefully all around the passenger side leaf spring seat on the axle. All that bracketry and weldments should be inspected.

Bolting on new shocks might be the easiest thing to do besides checking tire pressures, but shocks will not fix, or even hide, the issue you report.

These guys got ya covered pretty good.

I'll just add that it's not hard to check the hubs and ball joints to rule them out. Jack up the front and grab the wheel at 9 and 3 0'clock and give it a manly wiggle. Do the same at 12 and 6. A 2x4 under the tire to check the 12 and 6 motion will make it easier. The tire should be solid in all directions, but loose at 12 and 6 is probably ball joints, and loose from both directions would be hubs. A helper making the motions while you observe from a comfy spot on the ground would be good.

With the truck back on the ground have your helper saw back and forth on the steering wheel, look for any unwarranted play in the linkage.

And a LOL to Y2KW57 for "I might be exaggerating"! Dude I revere your precise language and descriptors, calling the panhard MIA in this case is probably apt, not exaggeration. :-X22

A pic is worth a thousand words. Got any?

Sorry for taking so long to get back, but the track has been at a friends house until we could find a time to bring it back to my place. So here are some pictures. If I need to take more, let me know what I should go looking for.

A few more pics

Looks like you have a fluid leak.

You'll do well to clean up the underside. I use Gunk Gel for those areas, but many ways to skin that cat. Once that is done, you'll be better able to see where your problems are.

Only definite thing I see is the sway bar bushings on the axle. Probably wouldn't hurt to do the end links while your there.

Yeah I just soaked it in some gun and let it sit on all the joints for 10 minutes then hit them with a brush and water. Darkness has set now so got to wait till it dries up. Probably reapply tomorrow. The fluid is coolant. When I have the reservior tank fulled to max it seems to drop about 3/4 of a gallon. I havent tracked down the culprit yet. Truck is parked until wobble solved. To dangerous to drive right now. Wobble has gotten more frequent and happens on less aggressive bumps, but this is also first time I have driven it without the hubs locked.

If I get chance later I will post up a great discussion (which I actually learned something from) about DW. But basically do you have larger than stock tires? Regardless, start with dynamic balaning your front tires.

It almost looks like fluid coming from the front differential the way it is patterned on the knuckle? Not that this is related to your original problem, but have you checked your front diff fluid level?

On your last picture, notice the polished wear next to the bushing as if its been sliding side to side.

Not long ago I hit some bumps and thought I had the death wobble. It felt like the wheel was coming off. Pulled over and got under the truck, pulled on everything, checked the lugs, found nothing. I drove home 30mph. Ordered new wheel hubs and changed those out. few days later it happened again, bad wobble. But I noticed that time it happened when I applied the brakes. Ended up being one of my front brake calipers was sticking. Just something to check.

Mine does it without braking, and does it when going over bumps. Im pretty sure makes brakes are good right now. I'll keep it in mind though.