Death Wobble

[540milotalon]

If I could afford it, I would be pulling my hair out right about now.
1996 Ranger, 5.0 A/T (4R70W) 2 wheel drive and 3.73 rear diff, all from totaled 1999 Mountaineer. 63K and 3.5 years since build.
Truck developed a terrible wobble in June, like it wanted to flip over, I knew shocks had worn out but truck build included shock, brakes and new tires all around.

I have changed front springs (replaced the original 3.0 with new 4.0 coils) rear springs (rear leafs had actually sat down some) front and rear shocks. Both upper and lower ball joints and outer tie-rod ends. I replaced the passenger side spindle and front end was aligned yesterday by one of the legendary local front end techs. On the ride home last night at one particular spot (65 mph) in the road where it had happened previously, it rode good. At a second bumpy spot at 60 mph it took to wobbling. As BAD as ever.

I called front end guy today and he said he would have to ride in it but as we talked he said he remembered one other time and he heard this complaint it was a full size pickup and it was tires.
Tires are 16” Cooper on Aluminum wheels with about 30K and still look good with no obvious wear patterns.
I dunno what to do? I do have another set of name brand tires with a little more wear on the exact same wheels to try for a guess.

 

[85_Ranger4x4]

Pivot bushings?

 

[Curious Hound]

Tires, wheel bearings, pivot bushings and radius arm. Bushings are about all that’s left. I would like to assume a legendary alignment tech would have noticed bad wheel bearings.

 

[540milotalon]

I will have to look at both "pivot bushings" and radius arms. I didn't see anything noticeable but I forgot to mention that as part of the work we repacked and set the front wheel bearings replacing one set of wheel bearings.

The wobble only comes when i get into a place in the road where there is a bumby or uneven wear area and then it does it and its right scary till you slow way down and get it to quit.

It is possible that my front end guy missed something but he knew why we tore into it.
It now has parts i should have changed on the initial build like front coils but i went for the cheap.
Except for the wicked wobble it rides and steers so much nicer........until it doesn't.

 

[JoshT]

Don't get too mad at the alignment guy. Something like the bushings mentioned may not be noticable until the suspension gets unloaded like going over bumps and uneven surfaces. If he wasn't super familiar with this suspension style he wouldn't necessarily have cought it on a normal inspection.

 

[scotts90ranger]

About the only thing not mentioned is the inner joint on the drivers side steering link or the one at the box, one thing these things apparently do in rusty locations is rust around the bolts that hold the steering box to the frame so I would give everything a good spirited shake...

I've run all sorts of janky stuff on my '97, bent wheels, currently only have one functioning shock, put like 40k miles on a set of tires I never had balanced, I set the alignment with calibrated eyeballs and a tape measure and I've never once had death wobble. Not to mention all the janky issues I've had with the '90, passenger front was 1" further back than drivers side, bent a drivers beam on a rock, drove for years with blown radius arm bushings, pivot bushings aren't great, alignment adjusted itself constantly, no sway bars, all the bolts on the radius arm crossmember to the frame were loose (should have been fine thread) and again, no death wobble.

The only time I've had death wobble was on my '00 Explorer with some used tires that were scalloped and one of the outer tie rod ends had worn out, anything over 50mph was downright scary...

 

[540milotalon]

Update, I have believed the wobble was in the rear of the truck. After changing the rear tires/wheels for the other set of used tires,
identical 16" Aluminum wheels no wobble but the truck still Felt weird in the rear. Pulled the new Monroe shocks off and they had zero resistance collapsing but did expand on their own.
I put on a set on coil over rear shocks on this past weekend and the wobble came back, (3) times at the 60 mph during the 20 mile trip to town yesterday. I am going backwards.

checking everything up front looks good, tight and nothing noticeable out of kelter.

 

[Curious Hound]

I've never heard of death wobble in the rear.

 

[85_Ranger4x4]

I've never heard of death wobble in the rear.

The original rear spring bushings in my truck were so shot I could barely stand in back of the truck, it just wiggled back and forth like Jello. It went down the road fine though.

 

[Curious Hound]

The original rear spring bushings in my truck were so shot I could barely stand in back of the truck, it just wiggled back and forth like Jello. It went down the road fine though.

Come to think of it, I have seen people walking in Walmart that had some pretty serious death wobble in the rear.

 

[540milotalon]

I don't know what to call it but "Death Wobble"?? It feels like it's going up and down and so violent at around 60 mph it's down right scary.
I have never rode in anything like it before and as one commenter above wrote, I rode or drove some sketchy stuff over the years.

 

[85_Ranger4x4]

Death wobble is more fore-aft oscillation caused by worn suspension components in the front.

Up and down is usually tire/shocks

 

[540milotalon]

It definitely got worse with addition of the coil over shocks, but it still had a weird feeling back there before changing them?
I am wondering if there is too much or too stiff of suspension on it?
I am thinking of putting some additional weight back there and see what happens?
Recap- 1996 Ranger, straight cab 7' bed. 8.8 rear and spring set for 5.0 Explorer. Now coil over shocks with 16" "E" rated tires.

I run China Freight ladder racks, cross over tool box and a couple hundred pounds of tools and misc things in the back.

 

[85_Ranger4x4]

What kinda pressure in your E rated tires?

 

[540milotalon]

40-45 I try to maintain 45 front and rear.
should I be at 60 like the F250?