I took my 1988 560SL out of the garage yesterday for the first time in 2 or 3 weeks. When I returned I found a red puddle on the garage floor (auto transmission fluid?) it was on the passanger side about 4 inches wide and 3 feet long. I guess it leaked as I was backing out of the garage. It was only a few ounces and only took a few paper towels to clean up. I checked the ATF level and it was fine. It has never leaked before and has not leaked since. My theory is that after the car sat for a long time there was excessive pressure when it was started and the excess was vented...... Is there an overflow/vent on the transmission? Any other ideas? I'm planning a long trip in the next few weeks and don't want to worry about this.

Ken