2000 Mercedes Benz ML320 transmition service

This is not correct. This transmission does require regular service usually around 80000 miles. The trans service should have included draining the tranny and replacing the trans filter and pan gasket. I've heard people refer to this trans, denoted as a 722.6 model, as a "lifetime trans". I am not sure where this rumor is coming from but all transmissions require service because the fluid breaks down over time and will eventually need to be replaced. Also MB has this listed as scheduled maintenance. Working at an MB dealer for years, I can assure you our transmissios are not lifetime and do require service.