A Complete Guide to the 1998-2005 Audi A6 Automatic Transmission Mount
Eliminate clunks, vibrations, and harsh shifting by understanding and replacing your A6's transmission mounts.
- Clunking noises and new vibrations are the most common symptoms of a failed mount.
- Your A6 has two identical transmission mounts; it is best practice to replace both at the same time.
- For a factory-smooth ride, choose an OEM-quality brand like Corteco.
- Driving with a bad mount puts extra stress on other expensive parts like engine mounts and axles.
Is Your Audi A6 Making a Clunking Noise?
If you're feeling a jolt or hearing a “clunk” when you accelerate, brake, or shift gears, a failed automatic transmission mount is a likely culprit. These mounts are made of metal and rubber, and after years of use, the rubber can crack, tear, or collapse. In some cases, the metal housing of the mount itself can break completely, leading to severe drivetrain movement. This is a common wear item on the Audi A6 C5 platform, and replacing them can make the car feel like new again.
Warning: Complete Failure is Possible
While the rubber portion usually fails first, the metal bracket of the mount can also fracture. A visual inspection is crucial. If you see cracks in the rubber, fluid leaking (on certain mount types), or the mount looks collapsed, it's time for a replacement. Don't ignore these symptoms, as a bad mount puts extra stress on your engine mounts, axles, and driveshaft.
Symptoms of a Failing Audi A6 Transmission Mount
- Clunking or Thumping Noises: The most common sign is a distinct clunk when you shift from park to drive or reverse, or during acceleration and braking.
- Excessive Vibrations: You may feel a new or increased vibration in the cabin, steering wheel, or floor, especially at idle or while accelerating.
- Rough Shifting: While it won't cause internal transmission damage, a bad mount can make shifts feel harsh or jerky because the transmission is moving out of alignment.
- Visible Movement: A mechanic can check for excessive engine and transmission movement by power-braking the vehicle (holding the brake and lightly applying throttle) in drive and reverse.
Choosing the Right Aftermarket Mount
Not all aftermarket parts are created equal. For your Audi A6, brands can be grouped into tiers based on their intended purpose and quality.
Tier 1: OEM-Quality Replacement
These brands aim to restore the original ride quality and performance. They are ideal for daily drivers where comfort is a priority.
- Corteco: Often an original equipment manufacturer (OEM) for German brands, Corteco parts are known to match the factory rubber hardness and quality, ensuring a smooth ride without excess vibration.
- Vaico: A well-regarded aftermarket brand for European vehicles, offering a reliable return to stock performance.
Tier 2: Standard/Budget Replacement
These brands offer a cost-effective solution but may not provide the same longevity or ride refinement as OEM-quality parts. They can be a viable option for budget-conscious repairs.
- URO Parts: A popular aftermarket option for European cars.
- Anchor, Westar, DEA, Pioneer Cable: These brands are widely available and provide a functional replacement at a lower price point. User reviews for these brands on performance-oriented vehicles are often mixed.
Pro Tip: Replace Mounts in Pairs
Your Audi A6 has two transmission mounts. It is highly recommended to replace both at the same time. If one has failed due to age and mileage, the other is likely not far behind. Replacing them in pairs ensures even support and prevents the new mount from being prematurely worn out by the old one.
How Much Does it Cost to Replace?
The cost will vary based on who does the work. This is a manageable DIY job for those with the right tools, but shop labor is also relatively affordable.
| Item | Estimated Cost |
|---|---|
| Aftermarket Transmission Mounts (Pair) | $50 - $175 |
| Shop Labor | $150 - $250 |
| Total Estimated Cost (Shop) | $200 - $425 |
Frequently Asked Questions
Is replacing the transmission mounts a DIY job?
Yes, for an experienced home mechanic. The job requires safely lifting and supporting the vehicle on jack stands, then using a floor jack to support the transmission while you unbolt and replace the mounts. It typically takes 1-2 hours. You will need basic metric sockets and wrenches (13mm, 16mm, 17mm are common).
How many transmission mounts does my 1998-2005 A6 have?
The automatic transmission version of the C5 Audi A6 has two main transmission mounts, one on the left and one on the right. They are identical and can be used on either side.
Will a new mount fix my transmission slipping?
No. A failing mount can cause harsh shifting or a feeling of delay, but it cannot cause the transmission to slip. Slipping is an internal transmission problem that requires a different diagnosis. However, replacing bad mounts can make a healthy transmission shift much more smoothly.
Are there any recalls for the Audi A6 transmission mount?
No. As of early 2026, there are no active safety recalls issued by the NHTSA for the transmission mounts on the 1998-2005 Audi A6. Failures are generally due to age and wear.
Technical Specifications
OEM Part Numbers: 8D0399151R
The 1998-2005 Audi A6 uses two identical automatic transmission mounts. They are typically a cast aluminum body with a rubber or hydraulic-filled bushing.
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The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.
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