If your Ram 2500 does any serious towing, hauling, or daily work, the factory rubber-bushed rear control arms and track bar are the first suspension components to show wear. Cracking bushings, vague rear-end feel, and axle shift under load are all signs that you are overdue for an upgrade. The Core 4x4 Aluminum Series rear control arms and track bar for the 2500 platform are built from 2-1/4-inch 7075 aluminum with 3-inch Rock Jock Johnny Joints — a direct bolt-in replacement with no spacers or shims required.
In this video, Gabby and Spence from Core 4x4 install the full rear suspension kit on their shop’s blue Ram 2500 — the same truck that tows their fifth wheel, hauls Jeeps to events, and does the heavy lifting every day. The factory bushings were cracking and showing wear, so it was time for an upgrade. This is a straightforward one-arm-at-a-time install with a focus on the measuring technique, torque specs, and the critical settling and re-torque process that most people skip.
Fitment: Ram 2500 2014–2024 (4th and 5th gen) | Also fits Ram 3500 | TRX version coming soon
The Aluminum Series: Why 7075 Aluminum and 3-Inch Johnny Joints
Core 4x4 has always offered a steel series for the Ram 2500 and 3500 — inch-and-three-quarter DOM with 2-1/2-inch Johnny Joints. The steel version is a more budget-friendly option and works great, but it requires spacers (included in the kit) to get the right fitment on the truck.
The Aluminum Series steps everything up. Here is what sets it apart:
- 2-1/4-inch 7075 aluminum construction — the same aerospace-grade alloy used in aircraft components, with inch-and-a-half thread engagement into the arms
- 3-inch Rock Jock Johnny Joints — significantly larger than the 2-1/2-inch joints on the steel series, built for heavy towing and off-road abuse
- Direct bolt-in replacement — no spacers, no shims, no modification required. The 3-inch Johnny Joint fits the factory mounting width exactly
- Double-threaded adjustability — both ends thread in and out, so you can fine-tune arm length while the arms are still on the truck
- Independent crush sleeves — you can torque everything in the air without creating bushing preload
Steel vs. Aluminum: Which One Should You Choose?
- Steel Series: Inch-and-three-quarter DOM, 2-1/2-inch Johnny Joints, spacers included for fitment. More budget-friendly. Great for daily driving and moderate towing.
- Aluminum Series: 2-1/4-inch 7075 aluminum, 3-inch Rock Jock Johnny Joints, direct bolt-in. Built for heavy hauling, frequent towing, and hard off-road use.
For this Ram 2500 — which tows a gooseneck and does heavy shop duty every day — the Aluminum Series was the clear choice. If your truck sees that kind of use, the bigger joints and direct fitment are worth it.
The Kit: What You Are Installing
The full rear suspension kit for this install includes:
- Two lower rear control arms — Aluminum Series, double-threaded with 3-inch Johnny Joints at both ends
- Two upper rear control arms — Aluminum Series, same construction
- One rear track bar (panhard) — Aluminum Series, adjustable with 3-inch Johnny Joints
On this truck, the factory bushings were starting to crack and show wear. The arms and track bar were still functional, but degrading bushings only get worse — especially under the kind of loads a working 2500 sees.
Setting Arm Length: The One-Arm-at-a-Time Method
Since this truck is leveled (not lifted), the arm lengths are not changing from factory. Spence uses the one-arm-at-a-time method: remove one factory arm, install the new Core 4x4 arm in its place, torque it down, then move to the next. This keeps three arms holding the axle in place at all times so it does not shift on you.
To match factory length:
- Set the new adjustable arm on top of the old factory arm (while it is still on the truck or on the workbench)
- Drop a bolt through both arms at one end
- Adjust the new arm until the bolt holes line up at the other end
- Make sure the ball centers (Johnny Joints) are sitting straight up and down when you measure — if they are rotated, your measurement will be off
- Lock the jam nuts to hold your length during install
Pro tip: Spence recommends doing the upper arms first. The upper bolt torque spec is lower (240 ft-lbs on all arm bolts) and you have better access to the mounting points, making it easier to get started before the lower arms add more hardware to work around.
Installing the Control Arms
Upper Arms First
With the truck on the lift, remove one upper factory arm. The new Aluminum Series arm drops right in — the 3-inch Johnny Joint sits in the factory bracket without spacers. Thread the bolts through, torque to spec, then move to the other upper arm.
Because these arms have independent crush sleeves, you can torque them in the air at full droop. The crush sleeve is not fused to the joint, so when you set the truck back down and the suspension compresses, the sleeve moves to its new neutral position with zero preload.
Lower Arms
Same process. Remove one factory lower arm, bolt in the new one, torque, move to the other side. The lower arms are bigger and heavier, but the install is identical.
If Your Axle Shifts
On a five-link rear suspension, if you remove multiple arms at once (or if the axle shifts slightly during install), you may find the last bolt does not quite line up. Two solutions from Spence:
- Ratchet strap: Run a ratchet strap from the axle to the frame and slowly pull the axle into position. This gives you more control than prying.
- Pry bar: Use a pry bar to lever the axle that last quarter inch until the bolt drops through. This works for small offsets.
Installing the Rear Track Bar
The track bar (panhard bar) is the last piece. Unlike the control arms, removing the track bar will shift the axle left or right because it is the component that holds the axle centered under the body.
Measuring Before You Remove
Before pulling the factory track bar, measure it. Spence uses the outside-to-inside technique: if both ends of the bar have the same diameter at the bolt holes, measure from the outside edge of one end to the inside edge of the other. This gives you an exact center-to-center dimension without trying to eyeball the bolt center.
On this Ram 2500, the rear track bar measured 35-7/8 inches center to center. That is the target for the new bar.
Watch for the Nut Tab
On the axle side, Ram trucks have a nut tab — a small metal tab welded behind the nut. When you impact the bolt off, the tab can swing around and cut your breather hose, brake lines, or wiring harness. Always hold the nut tab with vice grips or a wrench while you impact, or it will swing freely and damage whatever is in its path.
Setting the Length and Bolting In
With the factory bar off, the axle will shift. Set the new track bar to your measured factory length (35-7/8 inches on this truck), bolt both ends in, then use the double-threaded adjuster to fine-tune. The advantage of the double-threaded design is that you can make precise adjustments — in or out — while the bar is installed on the truck.
On this install, Spence had to adjust the bar slightly longer to get the bolts through (because the axle had shifted), then dialed it back to the exact factory dimension to pull the axle back to center.
Torque Specs and the Re-Torque Rule
This is the most important part of the entire install. Get the torque right, and do the re-torque.
| Component | Torque Spec |
|---|---|
| Control arm bolts (all four arms) | 240 ft-lbs |
| Control arm jam nuts | ~600 ft-lbs (as tight as possible) |
| Track bar end bolts | 140 ft-lbs |
| Track bar jam nuts | 250 ft-lbs |
Torquing in the Air Is Fine (With Johnny Joints)
Because every Core 4x4 arm has an independent crush sleeve inside the Johnny Joint, you can torque everything with the truck on the lift at full droop. The crush sleeve is not fused to the joint or the arm — when you set the truck back down, the sleeve moves to its new neutral position with no preload and no side effects.
If your suspension uses rubber or polyurethane bushings, never torque them in the air. The factory crush sleeve is fused to the rubber, and torquing at full droop locks the bushing in the extended position. When the suspension compresses, the bushing cannot rotate — it creates a preload that destroys the bushing prematurely.
Jam Nut Technique for Double-Threaded Arms
The jam nuts on the 3/4-ton arms are massive — inch-and-a-half threads. Spence could not find a crow's foot or wrench big enough, so he used Harbor Freight crescent wrenches with a cheater bar (pipe). Here is the technique:
- Alternate sides: Tighten one jam nut, then switch to the other end of the arm
- Gradually increase torque on both sides, going back and forth
- The Johnny Joints will rotate and look cockeyed as you tighten — this is normal. Left and right-hand threads rotate the joints in the same direction
- Stop when the arm tube will not spin between the two jam nuts
- Straighten the joints by hand afterward — they rotate freely in the housing once the jam nuts are locked
- Paint mark everything so you can see if anything moves during the settling period
The Settling Period and Re-Torque
This is the step most people skip, and it is the most important one:
- After the initial install, drive the truck for 300–500 miles
- Get back under the truck and re-torque every jam nut and bolt
- Check your paint marks — if any have moved, the components have settled and the re-torque will lock them into their final position
- After the re-torque, these will never move on you again
The settling period allows the threads, joints, and mounting surfaces to fully seat under real driving loads. Skipping this step is the number one reason people have jam nuts back off on adjustable arms.
Tools Required
- Floor jack and jack stands (or a lift)
- Socket set (18mm for factory hardware, appropriate sizes for your year model)
- Ratcheting 18mm wrench (highly recommended for tight spaces)
- Torque wrench (up to 250 ft-lbs minimum)
- Large crescent wrenches or pipe wrenches with cheater bar (for 1-1/2-inch jam nuts)
- Tape measure
- Penetrating fluid (PB Blaster or similar)
- Vice grips (for holding nut tabs)
- Ratchet strap (in case axle shifts during install)
- Pry bar
- Paint marker (for marking jam nuts after torque)
Why Upgrade Your Ram 2500 Rear Suspension?
The factory rubber bushings on the Ram 2500 rear control arms and track bar are designed for comfort, not longevity under load. If your truck tows, hauls, or sees off-road use, those bushings are the first thing to fail:
- Cracking and wear: Rubber bushings degrade over time, especially under heavy loads and temperature cycles. Once they start cracking, they deteriorate quickly.
- Axle shift under load: Worn bushings allow the rear axle to move laterally under braking and acceleration, affecting stability and tire wear.
- No adjustability: Factory arms are fixed length. If you have lifted, leveled, or even just sagged from towing, you cannot correct the rear geometry.
- Johnny Joint advantage: Core 4x4 Johnny Joints are spherical rod ends that rotate freely in all directions, handle massive loads, and can be torqued at any suspension position. They are rebuildable and do not require a strict greasing schedule.
Frequently Asked Questions
Related Content
- Ram 2500 Front Track Bar Install — the next video in this series, upgrading the front track bar on the same truck
- Why You Need Control Arms — educational overview of what control arms do and why upgrades matter
- Ram 3500 End Links & Track Bar Install — similar install on the Ram 3500 platform
Shop Ram 2500 Parts
Fitment: Ram 2500 / 3500 2014–2024 (4th and 5th gen). Questions: sales@core4x4.com | (385) 375-2104
