severe front end vibration need help long haul in 2 days!

[4x4 American]

When I'm driving along and hit a decent bump, there is a severe vibrating that feels like its coming from front end. It stays vibrating until i slow down to about 1-2 mph then it stops and i speed up and then next bump i hit it starts doing it again. the vibrating increases with speed and slows down when i slow down. once i start slowing down the vibrating slows down too it starts sounding/feeling like a slow moving train and then it stops. Drive shafts and U joints seem fine, I put in two new U joints 6months ago and they seem fine. When I jacked up front end, everything seemed ok, all the bushings can spin and they can lift up is that bad? I keep the truck well greased and I drive it alot I have a long haul back to school on tuesday so i want to try and fix truck asap. It started squeaking alot on the way home from work today. I had to take it through some thick mud at the farm and after that is when it started squeaking. Any help greatly appreciated! Thanks, Doug.

[dazedandconfused]

Try rotating the tires first and make sure the back of the wheels still don't have mud caked on them. Usually it's in the tierods and such that cause the death wobbles I've seen. My 01 dually would do that and it was the tires on the front.

[4x4 American]

Try rotating the tires first and make sure the back of the wheels still don't have mud caked on them. Usually it's in the tierods and such that cause the death wobbles I've seen. My 01 dually would do that and it was the tires on the front.

if I rotate the tires, won't it still vibrate?

[dazedandconfused]

If you have a bad tire on the front that could cause it. Do you feel it real bad in the steering wheel? The second gens are bad about trac bars and tie rod ends causing it. You can look out the window nest time it does it to see if tires are shacking left to right. I fought it in 2 dually's now. One was my 01 and the other was a 95 Ford F250 4x4. Tires were the issue with both.

[4x4 American]

If you have a bad tire on the front that could cause it. Do you feel it real bad in the steering wheel? The second gens are bad about trac bars and tie rod ends causing it. You can look out the window nest time it does it to see if tires are shacking left to right. I fought it in 2 dually's now. One was my 01 and the other was a 95 Ford F250 4x4. Tires were the issue with both.

I dont feel it real bad in the steering wheel. I feel it a little bit. I was just under the truck with the front end on the ground and i had my little sister turn the steering left and right. I noticed that there was a bit of play in the pitman arm bushing closest to the steering gear box. it moves up and down when the wheel is being turned left and right. I think that this may be the problem, but i dont get why it only starts vibrating when i hit a bump and then stops after i slow down. definitely a weird problem

[dazedandconfused]

My guess would be the shock of the wieght shifting that fast and sudden on the front wheels allows it to start the wheels wobbling.

[4x4 American]

My guess would be the shock of the wieght shifting that fast and sudden on the front wheels allows it to start the wheels wobbling.

that makes sense. i think this is the part i need: MEMDS914

[Mt. Tam trucker]

My truck does the same thing when the tires are worn. Something in the front end causes the tires to wear more on the inside. When this happens, I rotate the tires, the problem goes away until the front tires get worn again. I had the same problem on my 63 Scout, I put a steering stabilizer on it and never had a problem since.
Chris

[Tacoclaw]

If you've got a loose pitman arm joint, or any suspicious steering joints, you still need to fix it.

My old man got to go on a wild ride in the truck I have now when his pitman arm fell off one day. It never gave any indication it was going bad or anything, it just fell right off one day when he was making a left hand turn.

[4x4 American]

If you've got a loose pitman arm joint, or any suspicious steering joints, you still need to fix it.

My old man got to go on a wild ride in the truck I have now when his pitman arm fell off one day. It never gave any indication it was going bad or anything, it just fell right off one day when he was making a left hand turn.

holy cow what happened did he make out ok? i have the drivers side tires rotated and now im moving on to rotate the passenger side then im going for a test ride. I just ordered a new drag link from advanced auto they say it should be in tomorrow hopefully it will be. thanks to everyone for your advice, im hoping that i have the truck driving like gold again shortly

[Tacoclaw]

Yeah, he was fine.

By wild ride I mean he turned the wheel at a "T" intersection and the wheels didn't follow, which left him heading towards a guardrail with a 20 ft drop behind it.

Luckily the brakes were much better on it then than they are now.

[142autox]

Death wobble usually comes from a bump to the right tire. Replacing worn steering components usually fixes it. What happens is: RF wheel hits a bump and the energy transfers to the LF, then the the violent fight between the two of which one gets to be straight.

If you have worn steering components you can't control the fight between the front wheels and you will get uncontrollable death wobble. Adding a steering stabilizer will fix it, however its only a band aid.

If nothings worn or out of balance then its usually an alignment issue. Not enough castor can cause the "shopping wheel" effect. But usually a little negative toe will stop it.

Good luck!

[4x4 American]

Death wobble usually comes from a bump to the right tire. Replacing worn steering components usually fixes it. What happens is: RF wheel hits a bump and the energy transfers to the LF, then the the violent fight between the two of which one gets to be straight.

If you have worn steering components you can't control the fight between the front wheels and you will get uncontrollable death wobble. Adding a steering stabilizer will fix it, however its only a band aid.

If nothings worn or out of balance then its usually an alignment issue. Not enough castor can cause the "shopping wheel" effect. But usually a little negative toe will stop it.

Good luck!

Thanks for the great explanation! It makes much more sense to me now. Last night when I was tired as the dickens from workin a 13 hour shift on the farm I decided to get started on replacing the drag link that I got from advanced auto...that was a mess. I got the part of the drag link out of the side closest to the steering knuckle, and then I was trying to get the other end out from the pitman arm...well i had my neighbor turning the wheel back and forth and the other end of the drag link hit a brake line and snapped that mother clean in half...I got alot of work to do today and I still havent been able to get that damn drag link out of the pitman arm. prolly gonna go buy a pickle fork but the problem is that i got pissed last night and cut off the bottom part of the drag link going into the arm so now its basically a bolt stuck in the pitman arm. i dont know what i was thinking...

[4x4 American]

drag link wasnt the problem. there is slight play at 12 and 6 on the passenger front tire when i shake it hard when its in the air. may be king pins. where the steering shaft goes into the box in front of the gearbox is very loose. i dont think thats the problem though because when truck vibrates i hardly feel it in the steering wheel and steering is not affected. scratchin my head. tie rod ends seem tight. U joints seem fine, wheels spin fine when they are turned. still narrowing my as to what the problem is

[142autox]

Well, did you fix it yet?

As said earlier, if anything is loose it must be replaced. You should have 0 play in all steering links, including ball joints, and bearings. What kind of shape are your shocks in?

Chasing down the cause of a death wobble can be frustrating. I've had jeep things still do it after all components were replaced, very aggressive alignments done, and still had to resort to giant stabilizers. Fortunately for you, you have found some worn components, now replace all of them. You said you have vertical movement on the r/f. Most likely ball joints, but could be bearings but they would probably be quite noisy if that were the case.

Sorry, but you can't say "this is loose but its probably not the cause". If its loose you've probably found one of the problems.