Engine Mount - Torque Axis

This procedure replaces the torque axis engine mount (also called the dogbone mount or engine damper) on the 2019 Mercedes-Benz G-Class with 4.0L Turbo V8 engine, which controls engine torque reaction and vibration.

Warnings

Tools required

Parts

• Torque axis engine mount (dogbone mount) × 1 — Use OEM specification
• Engine mount fastener set (if fasteners show corrosion or thread damage) × 1 — Use OEM specification

Preparation

1. Park vehicle on level surface and engage parking brake
2. Turn off engine and allow to cool completely
3. Disconnect negative battery terminal and wait 10 minutes for system capacitors to discharge
4. Raise vehicle on lift or using jack and secure on rated jack stands at manufacturer lift points
5. Remove engine undertray or splash shield to access engine mount area from below (typically secured with multiple Torx fasteners around perimeter)

Procedure

1. 1

   Locate torque axis mount
   Confirm against Mercedes-Benz WIS whether the 2019 W463 with M176 V8 uses a discrete torque-strut/dogbone mount; this longitudinal-engine platform primarily uses left and right hydraulic engine mounts plus a transmission mount, and a transverse torque-axis mount as described may not apply. Verify the correct mount and its location before proceeding.
2. 2

   Install engine support
   Position engine support fixture across engine bay using fender protection pads, or position transmission jack with wood block under oil pan to support engine weight. Raise support until engine is just barely supported but not lifted. The goal is to prevent engine movement when mount is removed, not to lift the engine off its mounts.
3. 3

   Remove upper mount fasteners
   Locate the upper mounting bracket fasteners connecting the torque axis mount to the engine block. These are typically 2-3 E-Torx or Torx fasteners. Apply penetrating lubricant if fasteners show corrosion. Remove the fasteners completely and retain hardware. Note any alignment shims or spacers present. Note: Fastener count and drive type to be confirmed against Mercedes-Benz WIS/AR for the W463 M176 torque axis mount before ordering tools.
4. 4

   Remove lower mount fasteners
   Working from underneath, locate the lower mounting bracket fasteners connecting the torque axis mount to the front subframe or crossmember. These are typically 2-3 E-Torx or Torx fasteners accessed from below. Remove the fasteners completely and retain hardware. The mount may now be loose but may still be held by friction or alignment pins. Note: Fastener count and drive type to be confirmed against Mercedes-Benz WIS/AR for the W463 M176 torque axis mount lower bracket before ordering tools.
5. 5

   Remove torque axis mount
   With all fasteners removed, carefully work the torque axis mount out of position. It may be necessary to gently pry or wiggle the mount to break it free from alignment pins or corrosion. Maneuver the mount out from between the engine and subframe. Inspect mounting surfaces on both engine block and subframe for damage, corrosion, or cracks.
6. 6

   Clean mounting surfaces
   Use wire brush to clean mounting surfaces on engine block bracket and subframe bracket. Remove any corrosion, old thread locker residue, or debris. Inspect threaded holes for damage or stripped threads. If threads are damaged, they must be repaired before installation. Check alignment pins or locating features for damage.
7. 7

   Compare old and new mount
   Place old and new torque axis mount side by side. Verify that mounting bracket positions, overall length, mounting hole positions, and rubber/hydraulic element design match exactly. Verify part number on new mount matches application. Check that new mount moves freely if it has internal hydraulic damping (slight resistance is normal).
8. 8

   Position new mount
   Maneuver new torque axis mount into position between engine block and subframe. Align mounting holes with both upper (engine) and lower (subframe) brackets. It may be necessary to use engine support to slightly raise or lower engine for optimal alignment. Ensure any alignment pins or locating features engage properly before inserting fasteners.
9. 9

   Install lower mount fasteners
   Insert lower mounting fasteners through mount bracket into subframe/crossmember. Start all fasteners by hand to ensure proper thread engagement. Tighten fasteners in a cross pattern (if multiple fasteners) finger-tight initially. Do not torque at this stage.
10. 10

    Install upper mount fasteners
    Insert upper mounting fasteners through mount bracket into engine block mounting points. Reinstall any shims or spacers in original positions. Start all fasteners by hand to ensure proper thread engagement. Tighten fasteners finger-tight initially. Verify mount is properly seated and aligned before final torque.
11. 11

    Torque mount fasteners
    With mount properly positioned and all fasteners started, torque fasteners to specification. Torque lower (subframe) fasteners first, then upper (engine block) fasteners. Use a cross pattern if multiple fasteners are present. Torque fasteners to the OEM specification from Mercedes-Benz WIS/AR for this specific mount; do not rely on a generic range, as these fasteners are commonly torque-plus-angle (typically an M10 or M12 bolt with an initial torque followed by an angle stage). Verify exact values before final tightening. Note: Torque values to be confirmed from Mercedes-Benz WIS/AR; upper (engine) and lower (subframe) fasteners may differ and may require torque-plus-angle.
12. 12

    Remove engine support
    Carefully lower and remove engine support fixture or transmission jack. Allow engine to settle onto new mount naturally. Verify mount is not twisted or misaligned after engine weight is released.
13. 13

    Reinstall undertray
    Reinstall engine undertray or splash shield, ensuring all mounting points align properly. Install all Torx fasteners around perimeter and tighten securely. Verify no tools or parts have been left in engine bay or under vehicle.
14. 14

    Reconnect battery and lower vehicle
    Reconnect negative battery terminal and tighten clamp. Lower vehicle from lift or jack stands to ground. Start engine and allow to idle while monitoring for unusual vibration or movement.

Reassembly

1. Installation is performed in steps 8-14 above, mirroring the removal process
2. Ensure engine support is not removed until all mount fasteners are fully torqued
3. All mount fasteners must be torqued to specification in the correct sequence (lower then upper)

Verification

• Start engine and let idle. There should be minimal vibration transmitted to chassis compared to worn mount condition
• With engine running, have assistant gently apply throttle while observing mount. Engine should not rock excessively or contact surrounding components
• Perform test drive including moderate acceleration and deceleration. Monitor for reduced vibration, reduced engine movement feel, and absence of clunking from engine bay
• After test drive, inspect mount fasteners for proper torque (visual check for movement) and verify no contact between engine and body/frame
• Re-check all mount fasteners after 50-100 miles of driving as settling may occur

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