I have a 2004 Mazda 3s with 189K miles. I took it to a mechanic for changing the Automatic Transmission Fluid (ATF Flush). After reviewing the car mileage, the mechanic asked me when I has the last ATF flush done? I informed him that it was around 100K mile marker. He told me to “reconsider” and not to have the ATF flush as it may cause the transmission to break down (due to the build-up). I took his advice and left the shop.
I googled and found conflicting posts. Is he correct? Any advice?