I did a few searches in this forum to see if there were any posts on towing an ML350 4 down and could not find one. Anyone out there doing it and if yes what equipment are you using ?
For what it is worth: manuals can be wrong. The owner's manual for my Ford Fusion says NO even with the manual transmission I bought expressly for towing. The Ford website says NO. Even the dealer says NO. All are wrong. The owner documentation was not updated when this model got a new standard transmission on 2009. This car is perfectly safe to tow 4 wheels down.