Engine Mount - Rear

This procedure covers the removal and replacement of the rear engine mount on the 5.9L Cummins diesel engine, which supports the back of the engine and transmission assembly.

Warnings

Tools required

Parts

• Rear engine mount assembly × 1 — Use OEM specification

Preparation

1. Park vehicle on level ground and engage parking brake
2. Chock front wheels securely
3. Allow engine to cool completely if recently operated
4. Raise vehicle and support on jack stands at frame rails
5. Remove skid plate if equipped
6. Spray all mount bolts with penetrating oil and allow to soak for 10-15 minutes

Procedure

1. 1

   Support the transmission
   Position a floor jack with a wide wood block under the transmission, spreading the load across the pan rail or a solid case surface rather than concentrating force on the thin pan. Raise the jack until it just contacts with slight upward pressure, but do not lift the vehicle. This will support the weight when the mount is removed. Raise the jack until it just contacts the pan with slight upward pressure, but do not lift the vehicle. This will support the weight when the mount is removed.
2. 2

   Locate the rear engine mount
   Identify the rear mount assembly between the transmission tailhousing and the crossmember. On 4WD models, it is located at the rear of the transmission where it rests on the crossmember, just forward of the transfer case adapter. The mount consists of a rubber isolator with mounting brackets on both sides.
3. 3

   Remove the mount-to-frame bolts
   Remove the bolts securing the lower mount bracket to the transmission crossmember (socket size and bolt count vary by model year — verify against factory service documentation). Support the mount as you remove the last bolt to prevent it from falling. Support the mount as you remove the last bolt to prevent it from falling.
   Torque spec

   Engine Mount-to-Frame Bolts75 Nm (55 lb-ft)
4. 4

   Raise the transmission slightly
   Slowly raise the floor jack to lift the transmission approximately 1-2 inches. This will create clearance between the mount and crossmember. Monitor all surrounding components to ensure nothing binds or contacts exhaust.
5. 5

   Remove the mount-to-transmission bolts
   Access the upper mount bolts that attach to the transmission tailhousing or adapter plate. Remove these bolts (verify socket size against factory documentation, as it varies by transmission). You may need to work from multiple angles due to limited access around the transfer case on 4WD models.
   Torque spec

   Sensor Mounting Bolts11 Nm (8 lb-ft)
6. 6

   Remove the old mount assembly
   Carefully extract the rear mount assembly from between the transmission and crossmember. If the mount is seized or corroded, use a pry bar to gently work it free. Inspect the mounting surfaces on both the transmission and crossmember for damage or excessive wear.
7. 7

   Clean mounting surfaces
   Use a wire brush to clean the mounting surfaces on the transmission tailhousing and crossmember. Remove all rust, old rubber debris, and corrosion. Ensure surfaces are clean and flat for proper new mount seating.
8. 8

   Position the new mount
   Place the new rear mount assembly into position. Align the upper bracket with the transmission tailhousing bolt holes. You may need to adjust the jack height slightly to achieve proper alignment.
9. 9

   Install mount-to-transmission bolts
   Thread the upper mounting bolts through the mount bracket into the transmission tailhousing or adapter plate. Start all bolts by hand before tightening. Torque bolts to specification using a torque wrench.
   Torque spec

   Sensor Mounting Bolts11 Nm (8 lb-ft)
10. 10

    Lower transmission onto mount
    Slowly lower the floor jack to allow the transmission weight to settle onto the new mount. Align the lower mount bracket with the crossmember bolt holes. The mount rubber should compress evenly as weight is applied.
11. 11

    Install mount-to-frame bolts
    Insert the lower mounting bolts through the crossmember into the mount bracket. Start both bolts by hand to ensure proper thread engagement. Torque bolts to specification in a crossing pattern.
    Torque spec

    Engine Mount-to-Frame Bolts75 Nm (55 lb-ft)
12. 12

    Remove jack and verify installation
    Carefully lower and remove the floor jack from under the transmission. Visually inspect all mount bolts to ensure they are fully seated and torqued. Check that the mount rubber is not twisted or unevenly compressed. Verify adequate clearance around all components.

Reassembly

1. Reinstall skid plate if equipped, ensuring proper alignment with mounting holes
2. Lower vehicle from jack stands
3. Remove wheel chocks

Verification

• Start the engine and verify no unusual vibrations or noises from the rear mount area
• With engine running, shift through all transmission gears and observe smooth transitions without excessive movement
• Perform a test drive and monitor for any vibration, clunking, or drivetrain movement under acceleration and deceleration
• After 50-100 miles, re-check all mount bolt torque values to ensure nothing has loosened

Related trouble codes on this vehicle

Codes that commonly send this job to the bay — tap one for symptoms, causes, and diagnostic steps.

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