S8 Trans Sensor Causing Multiple Shift & Warning Issues

Having experienced similar automatic transmission issues on my 2011 Audi A7 3.0 TFSI, these symptoms strongly indicate potential transmission oil level problems rather than just a sensor fault. When my transmission started showing warning lights and rough shifting, the initial diagnosis also pointed to the sensor. However, further investigation revealed the transmission oil was significantly below required levels, causing overheating problems and improper gear engagement. The repair required: Complete transmission oil level check, System pressure testing, Replacement of transmission oil and filter, Recalibration of the transmission control unit, Clearing all fault codes This turned out to be quite serious as continued driving could have led to complete transmission failure. The grinding noise you describe matches my experience exactly, it was the transmission struggling due to insufficient lubrication. The symptoms you describe are actually common in high-mileage S8 models. I would strongly recommend getting a second opinion from another workshop specializing in Audi transmissions. They should perform a complete transmission diagnostic, not just sensor testing. Important: Do not continue driving the vehicle in this condition as it risks causing permanent transmission damage.

Thanks for sharing your experience. Same symptoms showed up on my S8 last year and it turned out being more than just the transmission oil temperature sensor. The whole transmission needed a thorough check and service. Did you end up getting it fixed? Would be curious to know the final repair cost and if any other issues came up after the repair was done. Just want to compare notes since transmission repairs can vary quite a bit in price.

I did get it all sorted and the good news is the transmission sensor fix resolved the core issue. The mechanic found the gearbox oil level was too low, which was causing those transmission issues we discussed. Total cost came to 365 Euro including parts and labor. Since having the faulty transmission oil temperature sensor replaced and the oil level corrected, the transmission has been shifting smoothly with no warning lights or emergency mode activations. No overheating problems either, which confirms the sensor was indeed the culprit along with the low oil level. My automatic transmission now performs perfectly, no grinding noises or rough shifting like before. Its been several months since the repair and no additional issues have surfaced. Looking back, catching it early helped avoid more expensive transmission repairs down the line. The price was reasonable considering the thorough diagnostic work and the fact that they properly identified both the sensor issue and the low oil level rather than just replacing parts unnecessarily.

After that discussion I decided to get it fixed. Found a transmission specialist who did a complete diagnosis. The total repair ended up costing 420 Euro, this included replacing the transmission oil temperature sensor, complete fluid change, and a thorough system check. During the repair they found the low oil level had caused some minor wear but caught it before any serious transmission damage occurred. Been driving for about 2 months now and the automatic transmission works perfectly, no more warning lights or emergency mode issues. The grinding noise completely disappeared after the repair and gear shifts are smooth again. Really glad I addressed this early rather than risking complete transmission failure. The repair cost was actually reasonable compared to what I initially feared might be needed. My advice to others with similar symptoms: dont wait too long and make sure to get a proper diagnosis from someone who knows these transmissions. These overheating problems can quickly lead to bigger issues if left unchecked.