Q8 Transmission Woes: Sensor Linked to Gearbox Failure

Having some experience with transmission issues, I faced a similar problem with my 2017 Audi Q7. The symptoms were nearly identical, rough shifting, grinding noises, and transmission warning lights. The automatic transmission showed similar behavior, going into limp mode after the warning lights appeared. After diagnosing, the workshop found the transmission oil level was too low, which caused the temperature sensor to give faulty readings and trigger the transmission issues. The repair process involved: 1. Complete transmission diagnostics 2. Oil level check and top-up 3. Sensor connection check 4. System reset and adaptation Total cost was 365 Euro for diagnostics, parts, and labor. The repair solved all symptoms and prevented potential long-term transmission damage. To help further with your specific case, could you share: Current mileage, When was the last transmission service, Whether you noticed any fluid leaks under the car, If the transmission issues started gradually or suddenly, Any unusual noises or behavior before the warning light These details would help determine if your Q8 is experiencing similar overheating problems or if there might be other transmission repair needs.

Thanks for the detailed response. I should mention my current mileage is 19788 KM with the last service done just 2 months ago. The transmission issues started quite suddenly during highway driving. The gearbox sensor warnings appeared without any prior symptoms. Interestingly, I had no fluid leaks or unusual noises before the warning light came on. The transmission repair shop mentioned the temperature sensor readings were erratic, suggesting a possible sensor malfunction rather than a transmission oil level problem. I will schedule a complete transmission diagnostic scan to verify if replacing the gearbox sensor might resolve these issues. Hoping its not a more serious transmission problem requiring major repairs.

Thanks for providing those additional details. Since you mentioned having the service done recently and no visible leaks, this definitely sounds similar to the sensor issue I dealt with on my Q7. The sudden onset during highway driving matches my experience, temperature sensors often fail abruptly rather than gradually. The erratic readings you mentioned are a classic sign of a faulty gearbox sensor. In my case, even though the transmission oil level was the root cause, the initial diagnostic scan also showed inconsistent temperature readings. Worth noting that proper sensor function is critical for the automatic transmission to operate correctly and prevent overheating problems. Since your vehicle is relatively new with low mileage, major transmission issues are less likely. From my experience, a failing temperature sensor commonly triggers these exact symptoms, rough gear shifting, warning lights, and emergency mode activation. The diagnostic scan should confirm whether its just the sensor. If so, the repair cost should be significantly less than what I paid since you likely wont need any transmission fluid work. The gearbox sensor replacement itself is typically a straightforward fix. Would be helpful to know what the specific error codes are once you get the diagnostic results. This would help confirm if your transmission issues match what I experienced or point to a different underlying cause.

Thanks for sharing that experience with a similar Q7 issue. My mileage is 19788 KM with the last service done just 2 months ago. The transmission issues started quite suddenly during highway driving. The gearbox sensor warnings appeared without any prior symptoms. Interestingly, I had no fluid leaks or unusual noises before the warning light came on. The transmission repair shop mentioned the temperature sensor readings were erratic, suggesting a possible sensor malfunction rather than a transmission oil level problem. I will schedule a complete transmission diagnostic scan to verify if replacing the gearbox sensor might resolve these issues. Hoping its not a more serious transmission problem requiring major repairs. I appreciate the detailed explanation of your repair process and costs. The fact that you also experienced sudden issues during highway driving makes me feel better about it likely being just a sensor problem rather than something more serious with the automatic transmission itself. I will update once I get the diagnostic results and specific error codes.