Engine Mount - Rear

Replacement of the rear engine mount on a 2007 Ram 3500 with 5.9L Cummins diesel engine, requiring engine support and removal of crossmember hardware.

Warnings

Tools required

Parts

• Rear engine mount × 1 — Use OEM specification
• Engine mount hardware kit (if corroded) × 1 — Use OEM specification

Preparation

1. Park vehicle on level surface and engage parking brake
2. Allow engine to cool completely if recently operated
3. Disconnect negative battery cable
4. Raise front of vehicle and support securely on jack stands
5. Spray all mount bolts with penetrating oil and allow to soak for 15-20 minutes
6. Inspect rear engine mount for damage, oil contamination, or separation to confirm replacement is necessary

Procedure

1. 1

   Position engine support
   Place a floor jack with a wood block under the engine oil pan, positioning it slightly forward of the pan's center. Raise jack until it just contacts the pan but does not lift the engine. This will be used to control engine position during mount removal.
2. 2

   Remove transmission crossmember skid plate (if equipped)
   Remove bolts securing the transmission crossmember skid plate. Set aside hardware for reinstallation. This provides access to the rear mount and crossmember bolts.
3. 3

   Support transmission
   Position a transmission jack or second floor jack under the transmission pan with a wood block for protection. Raise slightly to support transmission weight independently of the crossmember.
4. 4

   Remove crossmember-to-frame bolts
   Locate and remove the bolts securing the rear crossmember to the frame rails on both sides. Typically 4 bolts total (2 per side). Keep hardware organized as these may vary in length or have specific positions.
5. 5

   Remove engine mount-to-crossmember bolts
   Remove the bolts securing the rear engine mount to the crossmember from underneath. These bolts thread upward through the crossmember into the mount. Note orientation and any washers or spacers present.
6. 6

   Lower crossmember
   Carefully lower the transmission jack supporting the crossmember. The crossmember should drop down 3-4 inches, providing access to the upper mount bolts. Do not fully remove the crossmember unless necessary.
7. 7

   Remove mount-to-engine block bolts
   Remove the bolts securing the rear engine mount to the engine block. These typically bolt to a bracket on the back of the engine block. There are usually 2-4 bolts depending on mount design. Use a ratchet with extension to reach these bolts.
8. 8

   Remove old engine mount
   With all bolts removed, extract the rear engine mount from between the engine and crossmember. May require slight engine repositioning with the floor jack or use of a pry bar to create clearance. Inspect mount for failure mode (rubber separation, oil contamination, cracking).
9. 9

   Clean mounting surfaces
   Use a wire brush to clean the engine block mounting surface and crossmember mounting surface. Remove any rust, debris, or old rubber residue. Inspect threads in engine block for damage and chase with appropriate tap if necessary.
10. 10

    Install new rear engine mount
    Position the new rear engine mount between the engine block and crossmember. Align mount to engine block first and start upper bolts by hand. Use floor jack to adjust engine height as needed for proper alignment.
11. 11

    Install mount-to-engine bolts
    Thread in and hand-tighten all bolts securing the mount to the engine block. Once all bolts are started, torque to manufacturer specification in a cross pattern. If torque specification is unavailable, consult the manufacturer service manual before final tightening, as Cummins engine mount fasteners often require higher torque (commonly M12 ≈ 60-80 ft-lbs) — do not rely on a generic value for these safety-critical mount bolts.
12. 12

    Raise and align crossmember
    Using the transmission jack, raise the crossmember back into position aligning with the frame rail bolt holes and the lower portion of the engine mount. May require small adjustments to engine position with the oil pan jack.
13. 13

    Install crossmember and mount lower bolts
    Install the crossmember-to-frame bolts and snug but do not fully tighten. Install the mount-to-crossmember bolts from underneath and snug. With all bolts started, torque crossmember-to-frame bolts first, then torque mount-to-crossmember bolts, following the factory service manual torque specifications for the 2007 Ram 3500 rather than generic values, as chassis crossmember bolts on a 3500 are typically higher torque.
14. 14

    Reinstall skid plate
    If equipped with transmission crossmember skid plate, reinstall using original hardware. Torque bolts to 15-20 ft-lbs or until snug.

Reassembly

1. Remove transmission jack and engine support jack slowly, ensuring engine settles properly onto new mount
2. Verify all bolts are torqued to specification and no hardware was left loose
3. Reinstall any heat shields or components that were removed for access
4. Reconnect negative battery cable

Verification

• Lower vehicle and start engine, allowing it to idle
• Observe engine for excessive movement or vibration indicating improper installation
• With engine running, have an assistant shift through drive ranges while observing engine mount for proper load transfer
• Test drive vehicle and verify elimination of previous symptoms (clunking, excessive vibration, drivetrain movement)
• Re-inspect all mount bolts after 50-100 miles of driving to ensure they remain tight

Related trouble codes on this vehicle

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