I've run into a similar situation, and it's definitely not as simple as just hooking up a come-along and pulling. On a completely dead T590, the parking brakes and hydrostatic drive usually keep the tracks from rolling freely. Before forcing anything, I'd look up the proper brake release or towing procedure in the service manual. Taking a few extra minutes to do it the right way can save a lot of money in damaged drive components. I'm interested to hear what methods have worked well for others in the field.