1997 Ram 2500 Diesel 4x4 A/T

Ok Im going to start with the history of this truck:

I got the death wobble about 2 years ago and had a friend turn the wheel while I looked and it was obvious the track bar was moving too much.
I replaced the track bar and haven't had any death wobble since.
Got the front end aligned at tire shop approximately 1 year ago.
I got new tires last fall and in just a few months I noticed severe tire wear on the inside edge of both front tires.
I jacked it up and found the ball joints to be worn out.

So I got all new ball joints and I did the front wheel U-joints while I had it all apart.
I put it back together, rotated the tires so that the worn ones were on the rear, and the relatively new ones were up front.
Took it for a test drive, and the first bump I hit at 55mph started a death wobble. (this is the road and same bumps I drive daily right near my house)
So I rechecked my work and jacked it up again finding no play anywhere.
I thought this to be strange because the front end is now tighter than before, how could there be death wobble now when there was none before the new ball joints?
I came up with a theory that the worn out ball joints geometry was somehow counteracting the death wobble.

So since I have some pandemic down time, I decided its a good time to do the whole front end. I replaced all the tie rods, steering stabilizer, tightened the steering gear box, installed a steering gear bracket.
I measured all the tie rods and made the new ones match, it all went together easily with the wheels on the ground, so the alignment couldn't be that far off.
Took it for a test drive, same death wobble when hitting the same bumps.

So now I know everything is new and tight, it must be the alignment causing the DW.
I decide to do a driveway DIY alignment first.
I used levels strapped to the front tires to check toe-in, and I pulled strings from the rear tires.
Im attaching a sketch of what the strings revealed, and it appears my front axle is off center. As you can see, the string hits the driver's side front wheel before contacting the front edge of the rear wheel. No amount of toe-in or out could correct this. And on the passenger side, the string does not contact the front wheel at all.
The only remedy I see is to move the front axle toward the passenger side by 3/8".
How do I do this? Truck is not lifted, control arm eccentrics are set at passenger side: forward 1 tick, drivers side: 12 oclock/vertical
Should I set toe-in based on the center line of the front axle rather than the strings? Should I set toe-in entirely based on the levels and ignore the relationship to the rear axle? I tried setting toe-in using just the levels and still had death wobble. Any ideas?

 

Sounds like a toe out. Did you plumb off the wheels or tires? The tires will have a bulge at the bottom giving you a lean in reading...(Camber?)

An adjustable trac bar will allow you to shift your axle side to side but you are aligned about what my 01 is at, favoring the driver's side a bit.

Remember that alignment racks have slip plates for the front tires so the adjustments are true and not affected by tire bind.....

Do you have any movment with the truck sitting on the ground?

 

I didnt do any plumbing. I had the 4 ft. levels strapped to the tires horizontally across the center line of the wheel to establish a plane to measure toe in at the front and back of the tires. I did this with wheels on the ground on plywood. Camber is set by the ball joint sleeves at 0 degrees.
Right now I have the tires set to 1/8" toe in. Front of tire measurement is 79", back is 79-1/8"
There is no specification in the factory manual for toe in ***? I have read the alignment chapter several times, caster and camber specs are there, I cant find toe in specs. It tells how to set toe in, but not what it should be set at. ***.

Movement of what? If you mean steering components, none that I can detect. everything is new.

I have been making small adjustments, and then test driving it over and over. There is one specific bump in the road that I aim for that will set off the death wobble. Last test drive it started to wobble but immediately stopped as soon as I let off the gas. So I think Im getting closer.
How much toe in is permissible? 1/4"?

 

Where the trac bar places the axle is not an issue. Its has to be really out there 2"+ before it gets weird.

You likely do not have enough caster. Your worn balljoints probably gave you some extra. Factory caster spec may not be enough. I like to see ~5 degrees on any solid-axle truck. I believe there's cam adjusters in two of the control arms for that. If they are maxed out, then an adjustable/tubular control arm is the next step.

 

I still am thinking you need to set off the wheels, not the tires. With the weight of the truck the front tires will bulge out at the bottom and give an off reading. I cut a 2x4 to sit just inside the wheel rim with the center cap off when I aligned mine after replacing the bushing on my trac bar. I have notes on alignment specs the shop gave me back when I rebuilt my front end. I'll try to post them up...

 

My own equipment, which clamped to the rim of the wheel, had to be centered with its thumbwheel while rotating the tire to attain a zero reading...Then after lowering onto the turntable, I jounced the front end to settle it...In many cases on 2WD vehicles I could attach my angle gauge directly to the machined surface on the hub using the magnetic base...But improvised methods work also......Ben

 

Well since it's a 4X4...

Check the control arm bushings- if they rot you have your caster all over the place and that will lead to death wobble even if everything else is in spec.
(And if I just got camber and caster wrong.. English is far from the first language I learned and I just came home from my birthday party..)

 

I had already replaced the control arm bushings a few days ago. So Then I got it aligned at a shop. My toe in was perfect, only caster was off. I havent driven much yet, but so far I've gotten no death wobble hitting the same bumps that set it off before.
One caster eccentric is pointed forward and one backward now, which I thought was not allowed, so that is a bummer.

 

I didnt do anything near the bottom of the tire...I strap a level HORIZONTALLY across the center line of the tire (like 15" off the ground). If there is any bulging that high up it would be equal on both sides of tire. The wheels would be a better place to measure though, I agree.
I took it to get aligned and my toe-in was perfect, he only adjusted caster at the control arms.

 

Well, it should not be, but many times it is necessary to do it to get to the correct caster and not preload the bushing something fierce.
Just take a look at the bushings and see if one is pushed backwards and the other forwards. This should not be the case.
But then it's also interesting to see if both bushings are without tension against each other, but this is hard to measure.
But even if there's something a little amiss there, it will only lead to quicker wear of the bushings, but with toe-in and caster correct no death wobble in your nearer future.

 

I'm glad you got it fixed, death wobble is the worst when driving these pigs at speed....I found my aligment specs but they mirrored the factory service manual specs....I thought my guy had magic numbers but turns out he didn't.

 

Well Im back with an update after about 6 months and 4000 miles of driving:

The Death wobble is still there and I have severe tire wear on the inside edges of both front tires, just like before I did all this work.

Im not sure what to do next. The alignment shows me to be within specs, but the camber is near the lower limits (inside edge). Factory service manual says camber is not adjustable.
The only way I know to change camber is with the bushings on the upper ball joint. Should I even go down this path? If I put new bushings bushings in, how many degrees? The FSM gives no camber spec for my truck, since it is not adjustable....but the alignment report shows it within spec? so what is the spec? At the bottom of the chart in the FSM it says "preferred CROSS camber 0 degrees +/- 0.5 degrees" is that it?
My caster is on the high end of spec, it should be 3.10....would that effect camber angle at all?
Also, the thrust angle measurement confirms what I found with my string test (first post), and this is out of spec. Could this be contributing to the death wobble, because the vehicle is not being pushed straight?
I dont want to keep paying $100 to check the angle every time I make a change, and the guy who I aligned it says death wobble is a "bounce" and that its probably bad shocks....so I dont really trust his diagnostic abilities. The first alignment shop didnt even discover the worn out ball joints and adjusted my alignment anyway, sending me on my way with an out-of-spec alignment claiming "it was only out a little and you wont notice" so I stopped going there.
Ive always done all my own work on all my vehicles and I find this really frustrating because other mechanics just dont seem to care enough to really work with me to find the problem, or offer solutions that are clearly wrong.
What would you do?

 

Cross-camber is the difference in camber between both sides.

Caster shouldn't affect camber at all.... except the goofy stock 'Y' steering makes your toe really sensitive to caster angle. Your tire wear is very likely due to the toe 'changing on the fly'. It's one thing to set it up sitting still on a shop floor. The suspension, tires, & steering do different things at road speed.

I would switch to HD steering (to mimic almost every other solid-axle truck made) so that your toe is static, at which point you can do reliable alignments with a tape measure.

 

What is the condition of your tires?

What wheels are you running? Dodge had some crappy made steel wheels out there back in the 90's...out of round and out of true....

Shocks? Condition?

 

Tires were only a few months old when I replaced all the front end components....that's what started this whole front end project. I started noticing inside wear on the new tires.
I rotated the rears to the front when I did all the work and got it aligned, and they looked like new at that time.
When placed on the rear axle, the tires wear normally, so I have no reason to suspect the wheels. stock dodge steel wheels.
Shocks are billsteins, about 4 years old now.