SQ8 Trans Warning: Failed Temp Sensor Symptoms

Had nearly identical symptoms on my Q7 3.0 TDI from 2016. The rough gear shifting and grinding turned out to be critically low transmission oil level causing overheating problems. The transmission sensor was throwing false readings, making the transmission control unit reduce power to protect itself. This explained the limp mode. After proper diagnosis, the issue required: 1. Replacement of transmission oil level sensor 2. Complete transmission oil flush and refill 3. Transmission control unit recalibration 4. Replacement of worn transmission filter The repair was significant since running with low oil had started to damage internal components. Delaying the fix would have led to complete transmission failure. The transmission oil temperature sensor itself is a known weak point in these VAG diesel powertrains. Worth noting the symptoms got worse gradually over 2-3 weeks before the transmission warning light appeared. Key is finding a shop with proper diagnostic equipment for VAG transmissions, as general scanners often miss transmission sensor-specific codes. This repair requires specialized tools and expertise. Look for shops that regularly work on Audi/VW transmissions and can perform proper transmission oil pressure testing.

Thanks for sharing that experience. Dealing with similar transmission issues on my SQ8 right now, the gear shifting problems and warning lights match perfectly. Really helpful to know about the transmission oil sensor being the root cause. Quick question, do you remember roughly how much you paid for the complete repair? Also, has everything been running smoothly since the fix, or have you noticed any other transmission-related problems?

Just wanted to follow up about the costs and results. The faulty transmission oil temperature sensor was indeed the core problem, just as suspected. The repair shop found the gearbox oil level was too low, which triggered the sensor issues and warning lights. Total cost came to 365 Euro for everything, sensor replacement, fixing the oil level, and full diagnostic scan. Since getting it fixed 6 months ago, the transmission has been working flawlessly. No more rough shifting, grinding noises, or warning lights. The transmission repair specialist confirmed these transmission sensors are a common failure point, often leading to incorrect readings and transmission issues. Getting it addressed quickly prevented any serious damage to the transmission internals, which would have been much more expensive to fix. Would definitely recommend getting yours checked soon, as running with faulty transmission oil readings can cause lasting damage if left unaddressed.

I finally bit the bullet and took my SQ8 to a transmission specialist after getting such helpful advice here. The whole experience went way better than expected. They diagnosed the exact same transmission oil sensor issue you mentioned. Total bill came to 420 Euro for the sensor replacement, transmission oil change, and computer reset. The grinding during gear shifting completely disappeared right after the repair. The mechanic showed me the old transmission sensor, it was completely shot and sending wrong readings to the gearbox sensor unit. This explained the limp mode and rough shifting. Really glad I caught it before any major transmission damage occurred. The shop did a great job explaining everything and even showed me the live transmission data readings before and after the fix. Been driving for 2 weeks now without any warning lights or gear shifting problems. Definitely worth finding a specialized transmission repair shop rather than going back to my previous mechanic.