New to me c43 with 84,000 mi. I have driven the car 1200 miles and no problems till today. After about an hour on the road doing 65 mph all of a sudden the tranni felt like it was in nuetral. As i pressed on the gas the car went nowhere (rpms went up and the car slowed down) After 2 minutes or so in came back into gear. Drove it for another 45 minutes with no problems. What could this be? Could this be the sign of a major trasmission problem?

thanks
dave