I own a 2012 chevy impala. I recently changed the atf fluid with a valvoline full synthetic Dex 6. It shifts great but I noticed the transmition pan starts leaking. It wasn't leaking before. The car is high mileage over 200k miles. Should I change the fluid with conventional oem atf? Any advice is much appreciated.
Did you get a new pan gasket and torque the bolts to the proper tightness and in the correct sequence? Those are typically the cause of pan leaks. OEM fluid and Valvoline will both get past the gasket if you didn't put the pan and gasket on correctly.
If its from the pan area and you pulled the pan to drain, then its definitely an "installation" issue. If it had a drain plug only, then did you refill it with EXACTLY the same amount? Overfilling is bad news.
