93' Shorty

I posted a few months back about my trucks Shimmy and shake and even with the great feedback from members here I still have been unable to diagnose it. The problem is a Shimmy that is felt through the entire truck at certain speeds. It is a side to side type vibration that is visible on the steering wheel and makes my highway trips a living hell . I have much experience with vibrations of all sorts on all diffrent types of the 4x4's I have owned in the past. The truck shimmied when I bought it but because I got such a great deal on it and figured for sure it was a tire balance issue I went for it. My attempts at diagnosing the problems are as follows. First off I purchased new rims and tires and had them professionally installed and balanced. I then checked front and rear wheel bearings which were good. The problem is NOT driveline related. I replaced all suspension bushings with a poly kit. I installed new Rancho shocks all way round. My rear drums were checked and are good. I also pulled both rear axles to check for straightness which were fine. My front rotors are not warped. My front axle U-joints are good. All steering components are tight.

I have since isolated my problem to the front axle by removing my rear drive shaft, raising and blocking the front axle and letting her run in 4WD. I observe the problem as the front wheels spin and watch the whole truck shake as well.
The only thing I think it could be is the Kingpins. I have checked them a few different ways. I have raised the front axle and placed a bottle-jack under the knuckle and tried to detect any movement of which there was none. I have taken the load of the tire and wheel and had 2 people do everything possible to yank and twist and bounce the wheel but can see no movement in the kingpins at all. I know that these are the original kingpins and can't attest to the maintenance habits of the previous owner.
My question is can the kingpins be worn but not be apparent on outer inspection??. Does anyone have any other suggestions other than the basics allready covered. The truck generally drives well and has no evidence of front impact. I am at the end of my rope!!!.........Thx for stomaching the long-winded post and thx in advance for any help you can give.

jamesianglenn

Just grasping at straws here. Could it be engine vibration? Harmonic balancer problem? A pully on the power steering pump or other accessory. Or transfer case vibration. My first guess would have been an out of balance drive shaft, since I've heard of driveshafts not being balanced for higher speeds (55 mph limit days). All the stuff that spins has to be balanced. Good luck.

Redleg

The top king pin has a plastic, tapered bushing. Jack the front wheels off the ground to unloade them, then take the covers off. The spring will come with it, then pop the old one out and replace it. There is a slot to line up. Have you checked the u-joints in the axle? Hubs functioning and unlocking all the way?

Nuttymopar

Like Redleg said, quick easy fix for plastic cones on the kingpings. not a lot of $$ and fast too do.

To elimated tire shake, purchase some ceramic beads or some other type of internal balance system. I had a really bad shake also and even though tire balanced and re-balanced my tires, still there. I yank weights off and installed ceramic beads on the inside and what a difference. Took away almost ALL of my shake. The remaining shake now and then is from not having a steering stablizer while using 315x75x16 tires. Just too large some times and I need to get a stablizer.

mopar93

You eliminated the rear axle by disconnecting the rear driveshaft, but you didn't mention if you'd tried to eliminate anything up front. Jack it up like you did before and remove the front wheels. Run it again and see if the vibration is still there. That will eliminate the wheels and tires from being suspect.

I've seen many tires balanced by 'experts' that were still out of balance.

Another thing to check is the u-joints... again. A u-joint doesn't have to be sloppy to be bad. If it's binding up, it will cause a vibration but it won't feel sloppy or worn out.

Check for out of balance brake rotors. That's not too uncommon, especially with big brake rotors.

-Maurice

Tommy93w350

You're going to think I'm crazy, but I bet you have a W350 if so, the factory lug nuts doesn't keep the tires and wheels center on the lugs.

Jack up the front (one side at a time), loosen all lug nuts on that wheel, remove two nuts across from each other, replace with acorn type lug nuts. The acorn type nuts keep the rim centered on the lug. The factory did at one time but wear out very easily.

You can even see the difference. Before you change the nuts, spin the tire and watch the tread at the top move up and down. Then replace with acorn nuts, watch the tread at the top and its smooth while spinning.

A 30 year Dodge mechanic told me this and showed me on my truck during a lineup. I thought it was the kingpin also. He proved me wrong.

It pisses me off!!! All this time, it was something so simple!!!!!

Please tell me the difference and keep us posted!!!

Winr

"To elimated tire shake, purchase some ceramic beads"
Nuttymopar
I have never heard of this, but I am truly interested. I also have a vibration and I know it is the tire/rim combo but I cant get it balanced out. Where might one get some of these magic beads to try?

Nuttymopar

This is where I have been getting mine.

http://www.innovativebalancing.com/index.html

There are different types, (powder called equal, and these). The big trucks usually use the powder form I think. I tried that at first but I think they became wet inside and started to clump causing tire vibration again. Ceramic so far, I have had no problems. I just filled my winter tires and what a difference it made. I am doing one tire at time and going for a test ride and you can feel the difference each time.

freddy2pipes

93'Shorty, I hade a similar problem and I noticed the last time I packed the frt wheel bearings I set the preload to spec out of the dodge manual. This left a lot of slop in the frt end. So instead of Backing the nut off 120 deg like the book says, I turned the nut in hand tight and tried it. It almost eliminated the shake. You still need to torque the nuts to 50 ft lbs and rotate the wheels, but dont back them off as much as the manual tells you.

Hemi Cat

you didn't mention the speed the shimmy occurrs or the type of road you are on or what it does when you hit a bump. Still some unknowns. Try jacking the truck up and put "safety stands" under the axle tubes. Put a small block on the ground next to the tire and roll it slowly watching forfunout and irregular tread pattern and for up and down motion while rotating. Next put a 2 ft bar under the front tire and lift while watching the ball joints. Check the wheel bearings for noise and movement. Check the shocks for oil leaking at the shaft seal. Check the stabilizer shock on the tie rod for oil leaking at the seal. You didn't identify the truck you have so I don't know the suspension type you have. If you have leaf springs check the spring bushing and shackle bushings for any irregularities, off center, crooked, rubber spitting out. If it is coil, check the arm bushings for movement. After this set the truck down and get someone to turn the steering wheel half turn left then right one turn then left one turn while watching all suspension parts for excessive movement, especially the movement of the body to axle. If all checks out and road test shows the vibration is still there, switch the tires front to back and see if the vibration stays on the front or moves to the rear with the tires. Hope this helps.

Howard

93' Shorty

Hi guys and thx for all the ideas on my prob. I am currently in the process of checking my front wheel bearing preload as mentioned by Freddy2pipes. Tommy93W250's suggestion sounds viable however I have new acorn type lug nuts all 'round not factory. ALL suspension and steering components are either new or check out fine. Brand new Rancho 5000's each corner....new drag link and poly-urethane bushings on all leaf springs etc. I have 2 sets of rims and tires for my truck. I purchased my truck with brand new 35-12.50 R 16.5 BFG mud terrian KM''s on new Eagle alloy rims. I also run brand new 33" BFG all terrians on another set of rims as snows. Both sets of rims and tires have been balanced and rebalanced without solving my shimmy. To describe my shimmy in depth it occurs mostly on pavement and it is most pronounced at about 60KMH....or 35MPH, and then doesn't present itself again until about 105KPH...or 60MPH, where it is less annoying then slower speed. The vibration and shimmy are not isolated to just the steering wheel as you can see and feel the condition through the whole truck.
I have owned and daily driven this truck with this condition for about 8 months with the shimmy and in that time it has never worsened at all. I recently installed a new Rancho steering stab. which helped reduce the shimmy somewhat. When I changed from my 35" muds to my 33" snows I find the shimmy is more pronounced with the smaller tires. All driveline components are good and I have alot of previous experience on lifted 4x4's with driveline angles, u-joint vibrations etc. and none pertain to my truck. I will remove the top covers on my kingpins next and check the bushings as Redleg desribed. Has anyone ever experienced an out of balance hub and rotor assembly???. This will be my next area of scrutiny, as it is quite a large spinning mass and perhaps it could be out of balance, although they look good visually and my rotors seem O.K......

P.S. My truck is a 92 W250 reg. cab 4WD Thx again for everyones time and effort............................................ .......................................Mike.

Redleg

Also, haven't run into it myself, but check where the steering gear is mounted to the frame for frame cracks. I think that causes steering issues before driveline though.

andyr354

Also check the steering box for slack in the gears. This was the cause of a shimmy on my Jeep.

On the balance beads note, lots off offroaders run golf ***** in their TSLs and it works great. About 6 ***** per tire works well.

Alec

If the shimmy is caused by worn king pins, you would not get it running the truck on stands -- If you get the problem spinning the tires on stands it is unlikely to be a problem with any part of the steering. That said, replacing the upper king pin bushings AND SPRINGS is not a bad idea, pretty cheap, and easy. I do not recommend re-using the old springs.

If your locking hubs are disengaging properly, it is not a problem with the front axles, ujoints, or front drive shaft.

A hub or rotor could be out of balance. It is unlikely that it is the hub -- unless the hub is bent. You would likely have likely noticed this running it on the stands. Did you check for run out of the front hubs and tires when you did your experiment?

It could be a problem in the transfer case. You could try running the truck with both drive-shafts disconnected and see what you get. Also check the nuts on both output yokes while you are there.

Did you check your motor and transmission mounts?

Good luck, I hate these problems. Even if they aren't a real mystery, I normally get blind to the problem if I don't find it early on . . .

Alec