Transmission Mount

Remove and replace the transmission mount on a 2008 Dodge Viper with 8.4L V10 and manual transmission, including supporting the transmission and torquing all fasteners to specification.

Warnings

Tools required

Parts

• Transmission mount assembly × 1 — Use OEM Mopar specification

Preparation

1. Park vehicle on level surface and engage parking brake
2. Place wheel chocks behind rear wheels
3. Allow exhaust and drivetrain components to cool completely
4. Raise front of vehicle and support securely on jack stands at manufacturer lift points
5. Raise rear of vehicle and support securely on jack stands
6. Remove plastic belly pan if equipped to access transmission mount area

Procedure

1. 1

   Locate and inspect transmission mount
   Position yourself under the vehicle and locate the transmission mount at the rear of the transmission. The mount attaches the transmission tailshaft housing to the transmission crossmember. Inspect the current mount for signs of failure including cracks, separation, fluid contamination, or excessive deflection. Note the orientation of the mount for installation reference.
2. 2

   Support transmission weight
   Position a transmission jack or floor jack with a wood block under a flat, structural area of the transmission case. Raise the jack until it just contacts the case with minimal upward pressure—you want to support the weight without lifting the transmission. The transmission should rest on the jack with no load on the mount once fasteners are removed. Note: The transmission is heavy and must be fully supported. Ensure proper support with a transmission jack or sturdy floor jack before removing mount fasteners.
3. 3

   Remove transmission mount-to-crossmember fasteners
   Locate the fasteners securing the transmission mount to the crossmember. Remove the 2 bolts that attach the mount to the crossmember using a ratchet and appropriate metric socket. Support the mount as you remove the final fastener to prevent it from falling.
4. 4

   Remove transmission mount-to-transmission fasteners
   Locate the fasteners securing the mount bracket to the transmission tailshaft housing. Remove the 4 bolts that attach the mount to the transmission using a ratchet and appropriate metric socket. You may need to slightly raise or lower the transmission jack to access all fasteners comfortably.
5. 5

   Remove transmission mount
   With all fasteners removed, carefully lower the transmission mount assembly. It may be necessary to use a pry bar to gently separate the mount from the transmission or crossmember if corrosion or sealant is present. Remove the mount from the vehicle and set aside.
6. 6

   Clean mounting surfaces
   Clean all mounting surfaces on both the transmission tailshaft housing and the crossmember. Remove any dirt, rust, or old sealant residue using a wire brush or scraper. Ensure surfaces are clean and flat for proper mount seating and alignment.
7. 7

   Install new transmission mount to transmission
   Position the new transmission mount assembly at the transmission tailshaft housing, ensuring correct orientation matches the original installation. Thread in all transmission mount-to-transmission bolts by hand first to ensure proper alignment. Once all bolts are started, tighten them in a cross pattern to the specified torque value.
   Torque spec

   Transmission Mount Bolts65 Nm (48 lb-ft)
8. 8

   Align mount to crossmember
   Using the transmission jack, carefully raise or lower the transmission to align the mount with the crossmember mounting holes. The alignment may require small adjustments—take your time to achieve proper fit without forcing. The mount should align naturally when the transmission is at the correct height.
9. 9

   Install crossmember fasteners
   Once aligned, thread in the mount-to-crossmember bolts by hand. Verify that bolts thread smoothly without cross-threading. Tighten the crossmember bolts to the specified torque value.
   Torque spec

   Crossmember Bolts95 Nm (70 lb-ft)
10. 10

    Remove transmission support and verify
    Carefully lower and remove the transmission jack, allowing the transmission weight to transfer fully onto the new mount. Visually inspect the mount to ensure it is properly seated and compressed evenly. Check that no gaps exist between mounting surfaces and verify all fasteners are tight.
11. 11

    Reinstall belly pan and lower vehicle
    If a belly pan was removed, reinstall it with all original fasteners. Remove jack stands one at a time and carefully lower the vehicle to the ground. Remove wheel chocks.

Reassembly

1. Torque specifications are critical for proper mount function and must be followed exactly
2. The transmission mount should show even compression on both sides when weight is applied
3. All fasteners should be tightened in the sequence described: transmission side first, then crossmember

Verification

• Start the engine and engage the clutch while observing the transmission mount for excessive movement or vibration
• With engine running, shift through all gears checking for unusual vibration or clunking that might indicate improper installation
• Test drive the vehicle and verify no excessive drivetrain vibration, particularly during acceleration and deceleration
• After test drive, re-inspect all mount fasteners to confirm they remain tight and properly torqued
• Verify no contact between transmission and chassis or exhaust components throughout full range of suspension travel

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