Ram 3500 Long Arm Kit Install – True Four-Link Upgrade Guide

If your lifted Ram 3500 rides like a stagecoach on the highway and hops over every bump in the trail, the problem is control arm geometry. Lifting the truck moves the axle further from the frame, and the factory short arms end up at steep angles that fight suspension travel instead of allowing it. The Core 4x4 Long Arm Kit solves this by moving the upper and lower control arm mounts rearward on the frame, running longer arms at shallower angles, and restoring the kind of ride quality you had at stock height. In this guide we walk through the complete bracket-and-arm install on a 3rd-gen Ram 3500 sitting at 5-1/2 inches of lift.

Why Your Lifted Ram 3500 Needs a Long Arm Kit

At factory ride height your control arms sit nearly level, letting the axle travel straight up and down as the suspension cycles. As you add lift, the axle moves further from the frame and the arm angles get steeper. Instead of going up and down, the axle now has to swing forward and up over every bump. The ride gets harsh, the truck hops, and flexibility disappears.

A long arm kit moves the frame-side mounting points rearward, which lets you run a physically longer arm. That longer arm traces a wider arc, bringing the angles back toward level even at lifted heights. The result is a truck that rides and flexes the way it did at stock height—even at 5-1/2 inches of lift.

True Four-Link vs. Radius Arms and Drop Brackets

Not all long arm kits are equal. There are three common approaches to fixing control arm geometry on a lifted Ram:

• Drop brackets – bolt-on spacers that lower the factory mounting points. They help the angles, but they are a compromise—not a true geometry fix.
• Radius-style long arms – the upper arm is pinned to the lower, which limits side-to-side articulation. Off-camber flexibility suffers because the axle cannot cycle independently in both planes.
• True four-link – four independent arms, each with its own frame and axle mounting point. This is what the Core 4x4 kit uses. Your axle can move vertically and articulate side-to-side without restriction.

On these trucks, once you are past about 3 inches of lift, Spence at Core 4x4 recommends moving to a long arm kit. At the very least, run adjustable short arms—but for full drivability and flex, the true four-link is the move.

What Is in the Kit

The Core 4x4 long arm kit for the 3rd-gen Ram 3500 includes everything you need for the conversion:

• Frame brackets (driver and passenger) – powder-coated steel that sandwiches the frame rail and bolts through the existing crossmember holes plus three new drilled holes per side
• Upper control arms – bent to clear the body mount and provide tire clearance at full tuck, with left/right-hand threaded Johnny Joints for on-vehicle length adjustment
• Lower control arms – single-bend design, also adjustable with left/right-hand threads
• Cam washers – for centering the joints and bolts in the axle-side cam slots
• All hardware – mounting bolts, jam nuts, and crush washers

Tools You Will Need

• Drill with 9/16” and 5/8” drill bits (or an 11/16” hole saw—highly recommended)
• 13/16” socket
• 7/8” socket
• 15/16” socket
• 1-5/8” crow’s foot (for jam nuts)
• Torque wrench (capable of 250 ft-lbs or use a cheater bar)
• Angle grinder with a cutting wheel and flap disc
• Jack and jack stands or a lift
• Tape measure
• Etching tool, Sharpie, or center punch
• Rattle-can primer or paint for bare metal after drilling

Prep note: In the previous video in this series, all factory control arm brackets were cut off with a grinder and Sawzall, and the bare frame was painted. If you have not done that prep step, watch that video first—it is required before you can mount the new brackets.

Step 1: Remove Crossmember Bolts and Position the Bracket

Each bracket mounts to the frame using the two existing crossmember bolt holes plus three new holes you drill. Start by removing the two crossmember bolts on the side you are working on. Support the crossmember with a jack stand so nothing shifts—the opposite side will still have its bolts in.

Before sliding the bracket into place, run your hand along the factory weld where the crossmember meets the frame. There is often a piece of slag or a high spot from the factory weld. Grind any high spots flat so the bracket can seat flush. The top edge of the bracket should sit nearly flush with the weld behind it.

1. Slide the bracket up into position and thread in the crossmember bolts finger-tight to hold it.
2. Use a jack stand from below to push the bracket snug against the frame so it sits square.
3. Mark all three new hole locations with an etching tool or Sharpie—two 9/16” holes in front and one 5/8” hole in the rear.
4. Mark the backside of the frame as well so you have a reference for drilling straight through.

Step 2: Drill the Frame

Remove the bracket so you do not damage the powder coat while drilling. You can drill through the bracket if you prefer, but pulling it off first keeps the finish clean.

The two front holes are 9/16” and go through a single layer of frame (about 3/16” thick). The rear hole is 5/8” and passes through a section where two layers of the frame overlap—roughly 3/8” of steel total. This is the hardest hole.

Pro tip from the install: An 11/16” hole saw makes this job significantly easier and cleaner than a twist drill bit. If you have one, use it for the holes you can reach. It gives you a slight oversize that helps with alignment during final assembly. For the upper through-bolt hole, you may need a standard drill bit because the hole saw may not reach.

After drilling, hit all bare metal with rattle-can primer or paint before bolting everything down.

Step 3: Bolt the Brackets to the Frame

Slide the bracket back into position. Thread the upper control arm bolt through the frame and through the bracket first—this is your tightest-tolerance hole, so confirm it lines up before torquing anything else. If it is slightly off, you can ream the hole with a 5/8” bit to give yourself clearance.

Once the upper bolt is through, install and torque all fasteners:

Step 4: Set Control Arm Lengths

Before installing the arms, set their lengths on a workbench. For a 5-1/2 inch lift on this truck:

• Lower control arms: 34 inches, bolt to bolt
• Upper control arms: 32-1/4 to 32-1/2 inches, eye to eye

Measuring Bent Arms

The lower arms have a single inward bend, which is straightforward to measure. The upper arms have multiple bends to clear the body mount and provide tire clearance, making measurement trickier. Here is how to get an accurate reading on bent arms:

1. Make sure the Johnny Joints on each end are lined up parallel to the body of the joint housing.
2. Measure the outside of the bend and the inside of the bend.
3. Average the two numbers—that is your true center-to-center length.
4. Adjust using the left/right-hand threads until the average hits your target.

These measurements are your starting point. Once the arms are installed on the truck, you can pull a true straight-line measurement between the bracket bolts and fine-tune from there.

Step 5: Install the Arms

The kit includes cam washers for the axle side to center the joint and bolt in the cam slots. If you still have your factory cam bolts intact, you can reuse them for fine-tuning at the alignment shop. However, since all adjustment is now built into the threaded arms, the cam bolts are not strictly necessary.

1. Install the lower control arm first. Thread the axle-side bolt with a cam washer and hand-tighten, then connect the frame side.
2. Install the upper control arm. The upper bolt passes through the frame and into the bracket—this is why you confirmed fitment earlier.
3. Torque the axle-side bolts and the frame-side bolts per the specs below.

Driver Side: Body Mount Clearance

The upper arm has bends designed to clear the body mount. At full droop there is plenty of room, but at ride height and under compression the clearance tightens. When setting jam nuts on the driver side, orient the upper arm’s bend slightly outward to give extra clearance as the suspension cycles and the track bar pushes the axle toward the passenger side.

Step 6: Torque Specs and Jam Nuts

Jam nut torque on adjustable control arms is critical. A loose jam nut means the arm can change length while you drive. Here are all the torque specs for the long arm kit:

Retorque reminder: Jam nuts must be rechecked after the first drive and periodically after off-road use. A loose jam nut lets the arm unthread and change your alignment—or worse.

After the Install: Alignment and Break-In

Your bench measurements get you close enough to drive safely to an alignment shop. Because both upper and lower arms are adjustable, the alignment tech can make all caster and toe corrections through the arm lengths. The lower arms are easiest to adjust after installation, so tell the shop to make fine-tuning adjustments there.

After alignment:

• Retorque all jam nuts to 250 ft-lbs.
• Paint-mark every jam nut so you can see if anything moves.
• Recheck after 500 miles and after every off-road trip until you are confident everything is seated.

Why a Long Arm Kit Transforms Your Ram 3500

This long arm install is the final piece in a complete suspension overhaul that included a trailing arm kit for the rear, a new track bar and sway bar end links up front, and a 2.5-ton steering upgrade. Here is what the long arm kit specifically changes:

• Restored ride quality – shallower control arm angles mean the axle moves up and down instead of fighting forward, eliminating the harsh ride that comes with steep arm angles at lifted heights
• Better articulation – a true four-link allows independent vertical and lateral axle movement, so the truck flexes naturally off-camber
• Reduced axle wrap – longer arms with better geometry resist the twisting force that causes wheel hop under hard acceleration or braking
• On-vehicle adjustability – left/right-hand threaded Johnny Joints let you dial in pinion angle, caster, and alignment without removing the arms
• No compromises – unlike drop brackets or radius arms, a true four-link does not trade one capability for another

Fitment and Compatibility

• Ram 3500: 3rd generation (2003–2009)
• Ram 2500: 3rd generation (2003–2009)
• Designed for trucks with 3 inches of lift or more
• Works with the Core 4x4 trailing arm kit, steering upgrade, and track bar
• Requires prep work: factory brackets must be removed and frame painted before bracket install
• Install time: approximately 3–4 hours for bracket drilling and arm install (not including prep)

Frequently Asked Questions

Related Products and Videos

• Core 4x4 Ram 3500 Suspension Products
• Core 4x4 Ram 2500 Suspension Products
• Ram 3500 Steering Kits
• Johnny Joint / Rod End Grease
• Watch the Full Install Video on YouTube