Trailing Arm

Replace the rear trailing arm (also called radius arm or track bar) on a 4WD Dodge Ram 2500 with 5.9L Cummins diesel, restoring proper rear axle alignment and handling.

Warnings

Tools required

Parts

• Trailing arm (radius arm/track bar) × 1 — Mopar 52106647AB or equivalent
• Trailing arm bushings (if not included with arm) × 2 — Use OEM specification
• Mounting hardware kit × 1 — Use OEM specification

Preparation

1. Park vehicle on level surface and engage parking brake
2. Chock front wheels securely
3. Loosen rear wheel lug nuts while vehicle is on ground
4. Raise rear of vehicle and support frame rails with jack stands rated for vehicle weight
5. Remove rear wheels completely
6. Spray all trailing arm mounting bolts with penetrating oil and allow to soak for 15-30 minutes

Procedure

1. 1

   Remove rear wheel and locate trailing arm
   With the rear wheel removed, locate the correct component being serviced. Note: the Dodge Ram 2500 rear suspension is leaf-sprung and does not use trailing/radius arms — the rear may use a track bar running laterally from the axle housing to the frame rail. Radius/trailing arms are found on the FRONT solid axle of 4WD models. Confirm the exact part and its location before continuing.
2. 2

   Support rear axle assembly
   Position a floor jack under the rear axle housing near the differential to support the axle weight. Raise jack until it just contacts the axle and takes minimal load. This prevents the axle from shifting during trailing arm removal.
   ⚠Do not raise the axle higher than its normal ride height. Only support its weight to prevent dropping.
3. 3

   Remove frame-side mounting bolt
   Locate the trailing arm mounting point on the frame rail. Using an 18mm or 21mm socket (size varies by year), remove the frame-side mounting bolt. This bolt passes through the trailing arm bushing and frame bracket. Use a breaker bar if necessary, as this bolt is torqued high (verify exact spec in the factory service manual for your model year, as track bar bolt torque varies significantly). Support the trailing arm to prevent it from falling.
   ⚠Bolt may be seized. Apply heat carefully if necessary, avoiding fuel lines and brake components.
4. 4

   Remove axle-side mounting bolt
   Locate the trailing arm mounting point on the rear axle housing bracket. Remove the axle-side mounting bolt using appropriate socket (typically 18mm or 21mm). This bolt may require penetrating the rubber bushing. Once removed, the trailing arm will be free to remove from the vehicle.
5. 5

   Remove trailing arm assembly
   Carefully remove the trailing arm from the vehicle. Note the orientation and any washers or spacers present at either mounting point. Inspect the mounting brackets on both the frame and axle for damage, cracks, or excessive wear. Wire brush mounting surfaces clean.
6. 6

   Inspect and prepare new trailing arm
   Compare the new trailing arm to the old unit to verify correct length and mounting configuration. If bushings are not pre-installed, press new bushings into the trailing arm ends ensuring proper orientation. Check that all mounting hardware is included and inspect mounting brackets for debris.
7. 7

   Install trailing arm to axle housing
   Position the new trailing arm to the axle housing bracket. Insert the axle-side mounting bolt through the bracket and trailing arm bushing. Start the nut on the bolt but do not fully tighten yet. Ensure any washers or spacers are positioned as they were during removal.
8. 8

   Install trailing arm to frame bracket
   Align the frame-side end of the trailing arm with the frame mounting bracket. You may need to use the floor jack to slightly adjust axle position to align the bolt holes. Insert the frame-side mounting bolt through the bracket and bushing. Start the nut but do not fully tighten yet.
   ℹ️Minor axle position adjustment is normal. Do not force alignment as this indicates incorrect part or damaged brackets.
9. 9

   Position axle at ride height
   Use the floor jack to raise or lower the rear axle until it is at normal ride height (suspension at neutral position, not drooping or compressed). This is critical for proper bushing alignment and longevity. The trailing arm should be at its natural angle with no twisting force on the bushings.
   ⚠Torquing suspension components with weight off wheels or at incorrect ride height will cause premature bushing failure.
10. 10

    Torque trailing arm mounting bolts
    With the axle at ride height, torque both trailing arm mounting bolts to specification. With the axle at ride height, torque both mounting bolts to the factory specification for this specific fastener and model year. Do not substitute a generic control-arm value — consult the FSM, as track bar/trailing arm torque on these HD trucks commonly ranges 130-185 lb-ft depending on year and location. Torque the frame-side bolt first, then the axle-side bolt.
    ℹ️These are critical fasteners. Ensure torque wrench is properly calibrated and set to correct value.
    Torque spec

    Control Arm Bolts165 Nm (122 lb-ft)
11. 11

    Reinstall rear wheel
    Mount the rear wheel onto the hub, ensuring the mounting surface is clean. Thread all lug nuts by hand to prevent cross-threading. Tighten lug nuts in a star pattern, gradually increasing torque. Lower vehicle until tire just contacts ground to prevent wheel rotation.
12. 12

    Final torque and lower vehicle
    With the tire on the ground, torque all wheel lug nuts to the factory specification (typically approximately 135 lb-ft on the Ram 2500) in a star pattern. Remove jack stands and carefully lower the vehicle completely to the ground. Remove the floor jack from under the axle.
    Torque spec

    Wheel Lug Nuts183 Nm (135 lb-ft)

Reassembly

1. Verify all mounting bolts are torqued to specification with vehicle at ride height
2. Confirm no tools or parts are left under vehicle
3. Road test vehicle at low speed in safe area to verify no unusual noises or handling issues

Verification

• Test drive vehicle and verify steering returns to center properly and no pulling to either side occurs
• Listen for clunking or knocking from rear suspension over bumps, which would indicate loose hardware
• Visually inspect trailing arm mounting points after 50-100 miles for any loosening or movement
• Schedule alignment check if vehicle exhibits any pulling or unusual tire wear patterns

More procedures for this vehicle