I believe you'll be fine so long as you use a proper towbar, correct pins, airlines hooked, and safety chains. I've towed a few 818's behind my M35 and aside from the pushing going downhill, it was a smooth and slow ride. Your combo has weight on the Prime Mover vehicle on it's side in comparison to my Deuce. I was able to get to almost 40 mph with that 22,000 pound sled on wheels behind my truck. I even shifted into 5th a few times albeit briefly, it couldn't maintain it for long. I will add this, some say that you need to tie the steering wheel off. I can agree with this idea when towing a deuce as it has positive caster on the steer axle and wants to fight the other way, but a 5 ton tracks just fine and if you tie the steering wheel off, it will try to push your back end out when trying to make a tight turn at low speed.
