Maintaining your Audi A4’s transmission is crucial for its performance and longevity. While Audi suggests that the transmission fluid is “lifetime,” many experts and experienced car owners know that regular transmission oil changes can significantly extend the life of your transmission and ensure smoother shifting. This guide provides a step-by-step process for changing the transmission oil in your Audi A4, using readily available tools and demonstrating that this is a task achievable for the DIY enthusiast.
Step 1: Prepare Your Audi A4
Begin by safely lifting your Audi A4. It’s essential to have the car level to ensure accurate filling of the transmission fluid. Use four jack stands to raise your vehicle, providing a stable and level platform for the fluid change.
Step 2: Remove the Undertrays
To access the transmission and its drain and fill plugs, you’ll need to remove the front and rear undertrays. These are typically secured with a combination of T-25 Torx screws, 5mm Allen bolts, Phillips head screws, and sometimes large flathead screws. Carefully remove all fasteners and set the undertrays aside. This step exposes the transmission and surrounding components for the oil change procedure.
Step 3: Disconnect Power Steering Cooler
For better access to the front subframe and transmission plugs, disconnect the nut holding the power steering cooler to the front subframe. A 10mm socket is usually sufficient for this task. This provides a bit more room to maneuver and work around the transmission area.
Step 4: Loosen Front Subframe Bolts
The front subframe needs to be slightly lowered to gain optimal access to the transmission fill and drain plugs. Using an 18mm socket, carefully remove the six bolts holding the front subframe. It’s recommended to replace these bolts with new ones during reassembly, as they are often torque-to-yield bolts.
Step 5: Locate and Remove Fill and Drain Plugs
Identify the transmission fill and drain plugs. In the provided image, the fill plug is marked in red, and the drain plug in blue. Typically, a 10mm Allen key is needed for both. Crucially, always remove the fill plug first. This precaution ensures that you can refill the transmission after draining; if the fill plug is stuck after draining, you’d be unable to refill the transmission with new oil.
Step 6: Drain Old Transmission Oil
Position a drain pan beneath the drain plug and fully remove the drain plug to allow the old transmission oil to drain completely. Allow ample time for the fluid to drain out.
Step 7: Inspect and Reinstall Drain Plug
While the oil is draining, inspect the removed drain plug for any debris or damage. Also, examine the drained oil for any unusual particles, which could indicate internal transmission wear. Clean the drain plug and reinstall it. Note that unlike many vehicles, these plugs may not use crush washers. Torque the drain plug to approximately 32 ft-lbs, which is generally appropriate for this size bolt.
Step 8: Compare Old and New Fluid
Observe the condition of the old transmission fluid compared to the new fluid. As seen in the example, used transmission oil can degrade significantly over time, becoming darker and potentially losing its lubricating properties. This visual difference highlights the benefit of regular fluid changes.
Step 9: Fill with New Audi A4 Transmission Oil
Using a pump or syringe, begin filling the transmission with new, high-quality transmission oil through the fill hole. For this Audi A4, approximately 4.5 quarts of fluid are needed. Redline MT-90 75W/90 synthetic fluid is a recommended option, as used in the original guide.
Step 10: Fill to Overflow
Continue adding fluid until it begins to overflow steadily from the fill hole. This indicates that the transmission is filled to the correct level.
Step 11: Reinstall Fill Plug
Once the transmission is full, reinstall the fill plug and torque it to approximately 32 ft-lbs, similar to the drain plug. Clean any spilled fluid with brake cleaner to easily identify any potential leaks later.
Step 12: Reinstall Front Subframe and Undertrays
Reinstall the front subframe using new bolts. Torque these bolts to 90 ft-lbs, followed by an additional 135 degrees of rotation. This ensures proper bolt stretch and secure subframe mounting. Finally, reinstall the front and rear undertrays.
Step 13: Lower Vehicle and Test Drive
Carefully lower your Audi A4 back onto the ground. Take it for a test drive and experience the difference. A transmission oil change often results in noticeably smoother and more responsive shifting.
Conclusion
Changing your Audi A4 transmission oil is a straightforward maintenance task that can deliver significant benefits. By following these steps and using quality transmission fluid like Redline MT-90, you can help ensure the longevity and performance of your Audi A4’s transmission, enjoying smoother shifts and peace of mind knowing you’re proactively maintaining your vehicle. Regular transmission fluid changes, performed every 30,000 miles, are a worthwhile investment in your Audi’s long-term health, despite factory recommendations suggesting otherwise.
