This procedure covers the removal and replacement of the rear engine mount on a 2014-2018 Chevrolet Silverado 1500 with the 5.3L V8 EcoTec3 L83 engine.

Warnings

Tools required

Parts

• Rear engine mount × 1 — GM 15899695 or equivalent

Preparation

1. Park vehicle on level surface and set parking brake
2. Disconnect negative battery cable
3. Raise vehicle and support securely on jack stands at frame rails
4. Remove skid plate or lower engine shield if equipped
5. Inspect rear engine mount for damage to determine replacement necessity

Procedure

1. 1

   Support the engine
   Position a transmission jack or engine support fixture under the transmission oil pan with a block of wood to distribute load. Raise jack until it just contacts the transmission pan with slight upward pressure, but do not lift the engine yet. Ensure the support is stable and centered.
2. 2

   Remove rear mount-to-frame bolts
   Locate the rear engine mount on the transmission crossmember. Remove the two bolts securing the mount bracket to the frame/crossmember. These bolts thread vertically through the mount into the crossmember. Apply penetrating oil if bolts are corroded.
   ℹ️Mark bolt orientation if mount bracket has asymmetrical design to ensure correct reinstallation.
   Torque spec

   Engine Mount-to-Frame Bolts75 Nm (55 lb-ft)
3. 3

   Remove mount through bolt
   Remove the large through bolt that passes horizontally through the rear mount and transmission extension housing bracket. This bolt secures the mount to the transmission. Support the mount with one hand as you remove the bolt to prevent it from dropping.
   Torque spec

   Mount Through Bolt110 Nm (81 lb-ft)
4. 4

   Raise engine slightly
   Using the transmission jack or engine support fixture, slowly raise the engine/transmission assembly approximately 1-2 inches. This will create clearance between the mount and crossmember. Monitor all engine connections (hoses, wiring) to ensure nothing is being stretched or pulled tight.
   ⚠Raise engine slowly and stop immediately if resistance is felt or if any hoses or wiring become tight.
5. 5

   Remove rear engine mount
   With the engine raised, remove the rear mount assembly from between the transmission bracket and crossmember. Note the orientation of the mount and any spacers or washers for reinstallation. Inspect the transmission bracket and crossmember for damage or cracks.
6. 6

   Clean mounting surfaces
   Use a wire brush to clean the mounting surfaces on both the transmission bracket and crossmember. Remove any rust, debris, or old rubber residue. Inspect both mounting points for cracks, damage, or excessive corrosion that may affect new mount integrity.
7. 7

   Install new rear mount
   Position the new rear engine mount between the transmission bracket and crossmember in the same orientation as the original. Ensure any alignment tabs or locating features are properly seated. The mount should fit without forcing.
8. 8

   Install mount through bolt
   Insert the mount through bolt horizontally through the transmission bracket, mount, and opposite bracket side. Thread the nut onto the bolt but do not fully tighten yet. Ensure the bolt passes through cleanly without cross-threading.
9. 9

   Lower engine onto mount
   Slowly lower the engine/transmission assembly using the jack or support fixture until the mount is seated against the crossmember and the weight is transferred to the new mount. Ensure the mount seats evenly without binding.
10. 10

    Install mount-to-frame bolts
    Install the two bolts that secure the mount bracket to the crossmember. Thread bolts by hand first to ensure proper alignment, then snug them down but do not torque yet.
11. 11

    Torque all mount fasteners
    With all weight now on the mount and all bolts installed, torque the mount-to-frame bolts to 76 Nm (56 lb-ft) first. Then torque the mount through bolt to 110 Nm (81 lb-ft). Use a torque wrench and tighten in the sequence specified.
    ℹ️Torque fasteners with vehicle weight on mount to prevent preloading and premature mount failure.
    Torque spec

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

    Mount Through Bolt110 Nm (81 lb-ft)
12. 12

    Remove engine support
    Carefully remove the transmission jack or engine support fixture from under the vehicle. Verify the engine remains stable and properly supported by all mounts.

Reassembly

1. Reinstall skid plate or lower engine shield if equipped, torquing fasteners to specification
2. Lower vehicle from jack stands
3. Reconnect negative battery cable

Verification

• Start engine and verify no excessive vibration or movement
• With engine running, shift through all transmission gears and verify smooth operation
• Visually inspect mount for proper seating and alignment with no gaps
• Check that all mount bolts remain tight after initial engine run
• Test drive vehicle and verify no abnormal drivetrain vibration or clunking during acceleration or deceleration

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