Strut Mount - Rear

This procedure covers the replacement of the rear strut mount assembly on a 2007 Ram 3500 4WD with the 5.9L Cummins diesel engine. The strut mount connects the rear shock absorber to the frame and requires safely supporting the axle while removing the upper mounting components.

Warnings

Tools required

Parts

• Rear strut mount assembly × 1 — Use OEM specification or equivalent aftermarket
• Strut mount hardware kit (if not included) × 1 — Includes upper nuts and washers

Preparation

1. Park vehicle on a level, solid surface and engage parking brake firmly
2. Place wheel chocks in front of both front wheels
3. If fasteners appear corroded, spray upper shock mount nuts with penetrating oil and allow 15-30 minutes to soak
4. Gather all tools and new parts before beginning work
5. Verify new strut mount matches old unit before starting disassembly

Procedure

1. 1

   Raise and support vehicle
   Use the floor jack to raise the rear of the vehicle at the frame rail or designated jack point. Raise high enough to access the shock tower area from underneath. Place jack stands under the frame rails on both sides, ensuring they are secure and properly positioned. Lower the vehicle onto the jack stands. The rear axle should be supported so the shock is not fully extended; do not let the axle hang freely, which can over-extend the shock and stress brake lines.
2. 2

   Support the rear axle
   Position a floor jack under the rear axle tube near the side where you are replacing the strut mount. Raise the jack until it just makes contact and slightly compresses the suspension. This relieves tension on the shock absorber and prevents the axle from dropping when the strut mount is removed. The shock should be slightly compressed, not at full extension.
   ⚠️The axle must remain supported throughout this entire procedure. If the jack shifts or is removed, the axle will drop suddenly and may cause injury or damage the brake lines and wiring.
3. 3

   Access upper strut mount from inside bed
   From underneath the vehicle, locate the upper rear shock mounting point. On this solid-axle truck the shock's upper eye or stud bolts to a bracket on the frame rail, not to a strut tower accessed through the bed. Locate the upper mounting fastener securing the shock to the frame bracket.
4. 4

   Remove upper shock shaft nut
   Using the correct wrench for the upper shock fastener (verify size against the actual hardware, as this may be a through-bolt rather than a shaft nut), hold the shock shaft from spinning if a stud design is used while removing the upper fastener. Remove the nut, washer, and upper bushing/isolator. Note the order and orientation of all components for reassembly. The shock shaft will now be free from the mount but should remain supported by the axle below.
   ⚠Do not allow the shock shaft to fall through the mount. The shock is still attached to the axle and cannot drop far, but avoid damage to the shaft threads.
5. 5

   Remove strut mount bolts
   Locate the upper shock mounting bolt where the shock attaches to the frame bracket (verify fastener size against the actual hardware). Remove this bolt to free the top of the shock; the lower mount attaches to the rear axle. Keep these bolts as they are typically reused unless damaged or severely corroded.
   ⚠These bolts may be heavily corroded. Use penetrating oil and avoid stripping bolt heads. If bolts break, you may need to drill out and re-tap mounting holes.
6. 6

   Remove old strut mount
   Once all fasteners are removed, pull the old strut mount assembly away from the frame. You may need to maneuver it around the shock shaft. Inspect the mounting surface on the frame for rust, damage, or cracks. Clean the mounting surface with a wire brush to ensure proper seating of the new mount.
7. 7

   Install new strut mount
   Position the new strut mount onto the frame rail shock tower, threading the shock shaft through the center opening of the mount. Align the mounting bolt holes with the frame. Install the mounting bolts hand-tight initially to ensure proper alignment. Verify the mount is seated flush against the frame on all sides.
8. 8

   Torque strut mount bolts
   Using a torque wrench, tighten the strut mount mounting bolts to manufacturer specification. Without a verified torque value, consult the factory service manual for the rear shock upper mounting bolt specification before final tightening; do not rely on a generic estimate. Tighten in a cross pattern if multiple bolts are present to ensure even seating. Verify the mount does not shift during tightening.
   ℹ️Consult a factory service manual for exact torque specifications if available. The value provided is typical for this type of fastener but should be verified.
9. 9

   Install upper shock components
   Place the upper bushing/isolator onto the shock shaft in the correct orientation (match the order from removal). Thread the upper washer and nut onto the shock shaft. Hand-tighten the nut while ensuring the shock shaft remains centered in the mount opening.
10. 10

    Torque upper shock nut
    While holding the shock shaft to prevent spinning, torque the upper shock nut to specification. Without a verified torque value, consult the factory service manual for the correct rear shock upper fastener specification; typical rubber-bushed shock nuts are far lower than 70-80 ft-lbs and over-tightening will crush the bushing. Ensure the bushing is properly compressed but not over-tightened, which can cause premature wear.
    ℹ️Over-tightening can crush the rubber bushing and cause noise or premature failure. Under-tightening can allow the shock to separate. Verify proper torque.
11. 11

    Lower axle and remove jack
    Carefully lower the floor jack supporting the rear axle, allowing the suspension to return to normal ride height. Remove the jack from under the axle. Inspect the shock and strut mount for proper alignment and ensure no components are binding or misaligned.
12. 12

    Lower vehicle
    Raise the vehicle slightly with the floor jack, remove the jack stands, and carefully lower the vehicle to the ground. If replacing both sides, repeat the entire procedure for the opposite side before final testing.

Reassembly

1. Reinstall any bed liner sections or trim pieces removed for access to the upper mount
2. Double-check all fasteners are properly torqued before test driving
3. If both sides were replaced, verify both are installed identically

Verification

• With the vehicle on the ground, bounce the rear suspension and listen for any unusual noises from the strut mount area
• Visually inspect the upper mount from inside the bed to ensure proper seating and no gaps between mount and frame
• Test drive the vehicle at low speed over bumps to verify normal shock operation and no rattling or clunking
• After 50-100 miles, re-check the upper shock nut torque to ensure it has not loosened
• Inspect for any fluid leaks from the shock absorber that might indicate damage during service

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