VW Sharan Auto Trans Issues, Warning Signs & Fixes

I had a very similar issue with my 2004 VW Touran with the automatic gearbox. My experience with transmission repairs is moderate, having dealt with a few issues over the years. The symptoms you describe match exactly what happened to me, the slipping transmission, warning lights, and limp mode. After diagnosis, it turned out the undervoltage in the vehicle was causing the transmission control unit to malfunction, leading to those erratic gear changes. My workshop did a full system check and found the voltage issues were affecting the automatic transmission electronics. The fix included: Complete electrical system diagnosis, Replacement of faulty voltage regulator, Transmission oil level verification, Transmission control unit reset Total cost was 240€ and the transmission has worked flawlessly since the repair. Before suggesting specific solutions, could you share: Current transmission oil change history, Battery age and condition, Exact error codes from diagnostic scan, Does the issue occur more when the engine is cold or warm This information would help determine if your issue is identical to what I experienced, as automatic gearbox problems can have various root causes.

Thanks for the detailed response. I had the transmission oil changed at 120000km during regular service. The error codes from my recent diagnostic scan are P0730 and P0740. The transmission issues occur mainly when the car is warm, usually after 15-20 minutes of driving. The battery is fairly new, replaced just 6 months ago, and the voltage readings are normal according to my mechanic. I think my situation might be different from yours since the voltage is stable. The transmission performance continues to worsen, especially during highway driving. My mechanic mentioned the torque converter could be failing, but I wanted to explore other potential fixes before committing to such an expensive repair.

Based on those error codes and symptoms, your situation does seem different from my voltage-related issue. With P0730 and P0740, plus the problems occurring when warm, this points strongly to hydraulic fluid pressure problems in the transmission system. In my post-repair research, I learned these codes often indicate either a failing torque converter or worn hydraulic components inside the transmission. On my Touran, I initially hoped for a simpler fix, but the transmission problems eventually required more extensive work. The key factors that suggest a more serious issue than my original case: Problems worsen with warm transmission oil, Error codes specifically related to gear ratio and torque converter, Progressive deterioration of transmission performance, Issues persist despite good voltage and new battery Given your transmission oil was changed at proper intervals, worn fluid is likely not the primary cause. From both my repair experience and research, when these specific symptoms occur with those error codes, the torque converter typically needs replacement. The repair costs vary, but expect between 1200€-2000€ for a torque converter replacement including labor. While expensive, addressing it promptly prevents additional transmission damage that could lead to complete failure.

Thanks for sharing those insights. After comparing my symptoms with yours and getting your feedback, I am starting to accept that this might need more than just basic maintenance to fix. The transmission oil change history and good battery condition seem to rule out the simpler solutions I was hoping for. Since my transmission performance keeps declining and the error codes specifically point to the torque converter, it makes sense to address this before risking complete transmission failure. The repair cost range of 1200€-2000€ is steep but still better than needing a full automatic transmission replacement later. I will schedule an appointment with my mechanic to discuss the torque converter replacement. The fact that the issues mainly occur with a warm transmission and keep getting worse suggests waiting longer could lead to more expensive repairs. The hydraulic fluid pressure problems you mentioned match what my mechanic initially suspected. While I was hoping to avoid major transmission work on my older vehicle, it seems the torque converter repair is the most logical path forward given all the symptoms and diagnostic evidence.