There are several challenges that accompanied my search for the answer. The first problem was finding the correct year owner’s manual. The manual that came with the car had a date of 2008 (edition date and version are located on the back cover). For that year, towing capacity was higher. The second problem was that our pre-owned ML500 is not equipped with the towing package. To properly tow a trailer, the new owner would require a hitch, skid plate, and a software update to accommodate the weight. After a search through the dealership, I found the proper manual for a 2006 ML500.
A 2006 Mercedes-Benz ML500 tow rating is 5000 lbs.
According to the 2006 USA Edition D Operator’s Manual M-Class, “the maximum permissible gross trailer weight to be towed is 5000 lbs.” Note again that this applies to an M-Class properly equipped with the towing package. Members of the various Mercedes-Benz forums have claimed different capacities. And aftermarket hitches may have a different capacity than what is recommended by Mercedes-Benz. If I was the owner of a Mercedes-Benz ML500, I think I would go by the book. Who wants to replace a transmission or rear suspension? Be wise.