Transmission Oil and Filter Change 1994 Mercedes C280 W202 722.4

Opinions abound about how often to change the transmission fluid from every 20,000 to every 90,000 miles. I wasn&sure exactly when the last time the fluid was changed and about a year ago it was looking good. Picking the correct fluid is also challenging because transmission fluid technology and what manufacturers specify changes over the year. I have to think back to 1994 and what technology was available back then and determine what should be used. I ended up picking Pentosin ATF 1. I did run into a problem of leaking around the pan after putting it all back together. I couldn&figure out where I went wrong. But, I did end up getting a new genuine oil pan and genuine gasket. I also was more careful with the bolt-tightening sequence and bought a better torque wrench. My second attempt was successful. I believe the car shifts better, better downshift response and smoother shifting into reverse.