March 24, 2016

The "Death" of Death Wobble

Let’s start with a statement to ease your mind; Death Wobble is not YOUR problem; it’s not even a Dodge problem. Death Wobble is a problem that has plagued straight axle vehicles of all kind since their inception. Straight axle front ends are far stronger than their IFS counterparts but are equally as finicky once components start to wear. Combine the aforementioned with the weight of a Cummins diesel motor and you have a recipe for disaster. The good news is, with the proper precautions and maintenance, death wobble is 100% avoidable.

Death Wobble is most commonly attributed to one or many of the following parts:

     •    Tires
     •    Track bar
     •    Steering Components
     •    Control Arms

This article will be the first comprehensive write-up to cover the causes, diagnostics and solutions for death wobble specifically with the Dodge Ram, Heavy Duty trucks. This document will start with the first category and most common cause of Death Wobble, tires.

TIRES:
When choosing a tire for a Heavy Duty Ram, there are a few factors to consider; none more important than the load rating. These vehicles range from the mid 7,000s-9,000lbs. depending on how they’re equipped. Being the interface by which the vehicle maintains traction with the road, tire choice should not be taken lightly.

The first thing to consider is the load rating. Tires come in several load ratings which categorize tires based on their working load. We recommend running an E-Rated (10 Ply) tire. This is the case for all on and off-road, loaded and unloaded.  Most tires with an E-Rating have substantially stronger construction in their tread and sidewall than lesser rated tires.

Our favored brand happens to be Toyo. The construction of their E-Rated, Open Country options has been tested by our staff and customers time and time again with great result. We recommend running the largest tire size that one can fit given it provides the largest sidewall to assist with small-bump compliance. Running proper tire pressure is also imperative as mentioned in our wheel/tire article.

If you have more questions about how tires play into your ride quality and handling characteristics, take a look at one of our outher blog posts, Tires and Wheels: How Do They Affect My Ride?

Tire wear can also cause death wobble. We recommend rotating your tires every oil change and ensuring there is sufficient tread with no dry rot, cracks or odd wear in the rubber. In short, ensure you’re purchasing an E-Rated tire with ample sidewall and proper construction from a reputable manufacturer. Rotate them often and replace them when it’s time. This will minimize the likelihood that the death wobble you’re experiencing (or trying to prevent) is a byproduct of the tires you’re running.

In short, removing all avenues for road-forces to transmit into front end play will keep the vehicle death-wobble free.
 


TRACK BAR:
There are many names associated with the lateral link between your axle and frame rail; most common: Pan-Rod Bar, Panhard Bar, and Track Bar. We refer to this link as a track bar. The duty of this bar and importance of its condition cannot be overstated as it is BOTH a suspension and steering component. The factory uses a weak steel bar with small, vulcanized bushings at both ends.

The vulcanized bushings will only allow so much movement before binding. Given the strength needed to control this lateral movement of the front axle under the forces applied, ensuring there’s little to no deflection is imperative to avoid death wobble.


If your truck is lifted or running larger, aftermarket tires, we recommend replacing the worn out stock unit with Carli’s adjustable track bar. The Carli bar is universal as it will work with any stock height vehicle, leveled vehicle, or lift that utilizes a drop bracket meant for a stock length track bar.

The Carli Track Bars, CS-DPRB-03 & CS-DPRB-14, are constructed from 3/8” wall DOM. One side houses a 7/8” FK Bearing Uniball and the other side a custom durometer Currie Johnny Joint. The Johnny Joint/Uniball combination allow the bar to rotate without binding during articulation while maintaining a solid link with minimal deflection.

Ensuring your track bar is in good condition requires a two man team. Block the rear wheels for safety and have a friend start the motor and sit in the driver’s seat. Ensure the wheels are pointing straight ahead. Hold a flashlight on the upper track bar bolt and give the driver the “OK” to begin rocking the wheel back and forth. While under the truck, watch the upper track bar mount carefully. There should be no movement of the upper bolt or track bar.


    If….

•    The bolt and track bar are moving, improper torque was applied to the bolt during the installation of the track bar or it’s worked its way loose. This can oblong the mounting hole and has likely caused bushing failure. The mount must be fixed if the bolt hole was damaged and the track bar (if stock) must be replaced. If it's a Carli bar, the upper bushing (if PN: PRB-94 or PRB-03) or bearing (
if PN: CS-DPRB-03 or CS-DPRB-14) should be replaced once the mount is repaired. When installing the bar post-repair, ensure 14mm bolt (18mm Head) is torqued to 185 ft.lbs, 16mm Bolt (21mm head) torque to 215 ft.lbs., or 18mm Bolt (24mm head) torque to 275lft/lbs. Note that 2010-2013 Rams with a Carli Track Bar also require a stainless shim.
•    The bolt doesn’t move but the bar moves, this is a less severe version of the above bullet point. Improper torque was applied to the bolt during the installation of the track bar or it’s worked its way loose but there's not likely any damage to the mounting hole. The track bar (if stock) must be replaced. If it's a Carli bar, the upper bushing (if PN: PRB-94 or PRB-03) or bearing (if PN: CS-DPRB-03 or CS-DPRB-14) should be replaced once the mount is repaired. When installing the bar post-repair, ensure 14mm bolt (18mm Head) is torqued to 185 ft.lbs, 16mm Bolt (21mm head) torque to 215 ft.lbs., or 18mm Bolt (24mm head) torque to 275lft/lbs. Note that 2010-2013 Rams with a Carli Track Bar also require a stainless shim.
•    There is no measurable play in the Upper Bolt or Deflection in the Track Bar Bushing, the upper bushing in the track bar is good and the bolt has sufficient torque.  Put a torque wrench on the upper bolt to ensure the 14mm bolt (18mm Head) is torque to 185 ft.lbs.  If the upper bolt  is the 16mm Bolt (21mm head), torque to 215 ft.lbs.,

or 18mm Bolt (24mm head) torque to 275lft/lbs.
This same test should be performed to the bushing (if stock track bar) or Johnny Joint/Heim Joint (if Carli Track Bar) on the axle end of the track bar. The same diagnostics and solutions apply as above. If there is measurable play found in a Carli Johnny Joint, a new Johnny Joint (PN: AP-JJPRB16 or AP-JJPRB18) or Heim Joint (PN: AP-TBRE) can be ordered from your local Carli Suspension dealer or online retailer depending on which model bar is installed on the vehicle. Ensure to take note of the eye to eye measurement of the track bar before removing the old Joint. Once the old Joint is removed, thread the new one in, set it to the exact measurement of the bar when it was removed and tighten the jam-nut to 150ft.lbs using Red Loctite on the Jam-Nut threads. Install the rebuilt track bar and tighten the 14mm bolt (18mm Head) to 185 ft.lbs, 16mm Bolt (21mm head)  215 ft.lbs., or 18mm Bolt (24mm head) to 275lft/lbs.

Performing the above will ensure your Death Wobble is not being caused by your track bar!


STEERING COMPONENTS:
Ram’s are notorious for failed steering components as the high-leverage design of the front end stresses the wearable ends and gearbox. This makes for tight steering and minimal wheel input with a new steering gear and new linkage; however, the steering becomes increasingly unpredictable when worn. To diagnose play in the steering, start at the top!

Steering Gearbox:
Block the rear tires for safety and have a friend sit in the driver’s seat and start the vehicle while you get underneath the truck and watch the sector shaft and intermediate shaft. Instruct your helper to begin rocking the wheel back and forth. Start with very short movements. While they’re rocking the wheel, keep your eye on the movement of the intermediate shaft-steering gearbox input (the part of the gearbox that faces the firewall denoted by Arrow A) vs. the amount of movement of the sector shaft (the shaft protruding from the gearbox to which the pitman arm connects denoted by Arrow B). If you can get the intermediate shaft to move without moving the sector shaft, the gearbox is worn and should be replaced. These two move at different ratios so ensure that the dead spot in the box justified replacement. Also watch for vertical and horizontal movement of the sector shaft within the housing as this also signifies a worn Steering Gearbox.


It's a good idea to lightly grasp the sector shaft (allow it to spin with a loose grip) while your partner is rocking the wheel to see if any popping can be felt; this is indicative of a sector shaft in need of replacement, but not a cause of death wobble.

Many also elect to stabilize the steering gearbox as the factory doesn’t provide enough stabilization for the amount of leverage applied to the box. This will cause the sector shaft to oscillate when worn rather than rotate; thus causing play and destroying the gearbox. Many aftermarket manufacturers make a brace that uses the sway bar mounting locations to brace the sector shaft on the outermost leverage point to combat steering wander and death wobble. There are several manufacturers that make these braces. We favor the style pictures. The bracing link comes off the bottom of the square stock, under the sway bar. This unit also provides clearance for the Carli Torsion Sway Bar, if equipped.

If no independent movement of the intermediate shaft and sector shaft can be detected, the intermediate shaft and gearbox are in good shape and you can move onto the steering linkage.

Steering linkage:
Just as with the track bar test, block the rear wheels and have a buddy get behind the wheel, turn the motor on and watch for any movement in the steering linkage at all points of connection. Specifically, watch the tie rod ends and ensure they have NO visible play. Any visible popping or plunging of the rod end and the tie-rod end, or that portion of the linkage, should be replaced.



There are two types of steering linkage factory installed on the front ends of these vehicles; these are most commonly referred to as: “Y” and “T” style. These can be identified by the following picture:


“Y” style was factory installed on 94-2008 Ram 2500 and 3500 trucks. In some 1998-1999 trucks, there was an option for the “T” style steering but it is mainly found on the 2008.5+ vehicles; thus it’s often referred to as the “08.5+ steering upgrade.” Mopar no longer manufactures or supports the “Y” style steering so the logical upgrade path would be to purchase the “T”. We find the Y-style has better geometry and less bump steer while the T style is stronger but more susceptible to bump steer in all circumstances. Given the strength increase of the 08.5+ linkage, we recommend upgrading to the T style as any strength upgrade is welcomed in the Ram’s front end.

When installing the steering upgrade or aligning the vehicle, ensure to properly position the tie-rod ends. Adjustment of the alignment sleeve on the tie rod or drag link (to achieve proper toe-in/steering wheel position) “clocks” the tie-rod end whichever way the sleeve is spun. ALL tie-rod ends should be perpendicular to the steering knuckles and pitman arm at ride height with the weight of the vehicle on the suspension. This will ensure proper operation during articulation. If the above procedure isn’t followed, improper orientation can cause steering linkage to bind and fail.

 
How to properly align the Vehicle:
“Y” Style:  0” Toe In. Ensure the tires are pointing straight ahead. Put a straight edge to the tire sidewall that extends beyond the front and rear of the tire. Have a friend do this on the other side as well. Run a tape measure under the truck from straight edge to straight edge and adjust the steering linkage until the measurements are identical; you’re now properly toed for the “Y” Linkage.

“T” Style:  1/16”- 1/8” Toe In. Follow the same procedure as aligning the “Y” linkage until the front measurement is 1/16”-1/8” less than the rear measurement; you’re now properly toed for the “T” Linkage.

Again, after the above alignment is performed, please ensure the tie-rod end – Knuckle/Pitman Arm connections are perpendicular at ride height to allow for the joint to function properly during articulation! Not completing this last step can lead to failure of the steering linkage.

The above addresses toe, camber is non-adjustable and Carli’s technicians always adjust caster by pointing the position marker on the lower control arm eccentric bolts to the 12 o” clock position (6 o' clock on the 13+ 3500 or 14+ 2500). This is not the perfect location for every truck but a great starting point by which to adjust caster. If the steering is loose, add a bit of caster by leaning the adjuster forward slightly and repeat; if it’s overly stiff, reduce caster slightly by rocking the adjuster rearward and repeat. Please ensure the eccentric bolts are not pointing in opposite directions as this will accelerate wear on the control arm bushings. Whatever adjustments are made to one side should be mirrored on the other.

Steering Stabilization:
The next step is ensuring proper stabilization of the steering linkage.  First and foremost, never run without a steering stabilizer. As stated above, there are a lot of forces being applied to the steering linkage at all times and these forces should be mitigated with some type of stabilizer. To stabilize the steering, Carli offers a proprietary stabilizer with a custom valving profile for increased control. The stabilizer is a Stainless Steel Body, Billet Rod Ends and achieves misalignment by way of two, ½” serviceable bearings. This Stabilizer can be run in a low-mount (factory location on “T” style or adapted to the “Y” style with a clamp we manufacture) or a high mount as an auxiliary/secondary stabilizer.

These stabilizers are also adjustable for radial pulls in both direction; more information on this can be had from a Carli retailer.

Once all steering linkage is tight, properly aligned, stabilized and free of play, you can move onto the ball joints.




Ball Joints:
Another common cause of death wobble in the 2003-2012 HD Dodges is worn ball joints. Stock joints normally last anywhere from 20,000-60,000 miles but we’ve seen both extremes from sets lasting 5,000 to 100,000 miles. Due to this inconsistency, it is imperative to check your ball joints for play often.  You will, again, need a buddy to help you in the diagnostic process. Procedure:

•    Block the rear tires for safety and jack up the font of the truck; then, support the axle with proper jack stands once the weight of the truck is off the ball joints.
•    Have your assistant place their hands at 12 and 6 o’ clock and rock the tire vigorously while you watch the upper and lower ball-joints for deflection. This will highlight play in the uppers more so than the lowers.
(See Arrow A and B)
•    If there is substantial visible movement in either, they should be replaced. A very small amount is OK.
•    If it’s difficult to detect movement, have your assistant apply more leverage to the bottom of the tire to increase the chance of deflection in a bad joint. This will highlight play in the lowers. If you found that your ball joints are out of spec, we do offer HD ball joints with a lifetime warranty.
•    While the weight of the vehicle is off the joints, have your assistant place his hands at 12 and 6 o’ clock and rock the tire with force and watch for deflection in the wheel bearing. If there is play, replace the wheel bearings as this is far easier to do while you’re installing your new ball joints than to tackle separately. Bad wheel bearings can also be diagnosed by a “humming” sound when driving around corners or grinding noise when spinning the tires.



•    Also, check the axle u-joints while the truck is off the ground. Inspect the U-joint caps for rust. If rust is found around the seal, there is rust contaminating the u-joint and it should be replaced. Next, check them for play. If the axle u-joints are bad, play will be detectable by grabbing and moving them by hand. If they’re tight, move onto the next step in the diagnosis.

  

Once you’re confident your tires are in good shape, the intermediate shaft, steering gearbox, steering linkage, ball joints, unit bearings, and u-joints are all free of play, you can move onto the least common cause of Death Wobble, the control arms.


CONTROL ARMS:
Control arms have only been the cause of death wobble in a few cases we’ve experienced. After all of the above troubleshooting procedures have been performed, the death wobble should disappear. If not, check the control arms for wear. The factory arms are weak, stamped steel with vulcanized bushings. These bushings are prone to developing play and dry rot.

If the truck has stock control arms, remove and inspect all joints to ensure there are no tears/dry rot in the vulcanized bushings. If all is tight and the death wobble is gone, you’ve successfully completed the diagnostic of the entire front end. If the bushings are worn or torn, replace the arms. Stock arms are rather expensive and this would be a great time to look into upgrading.

As stated above, reducing friction and play will reduce the likelihood of any wobble picking up momentum in your front end. Carli’s control arms should only be utilized in a leveled application, although several trucks have successfully run them on stock height vehicles, we do not recommend it (radius arms to be utilized in 6” applications).