Some many years ago I was a wind farmer. They were replacing a bunch of old turbines on a steep ridge across the highway from the field I worked at. The crane company they hired was trying to get a 100 ton Terex RT up a steep embankment at the top of a ridge, the crane simply would not get enough traction to climb the embankment. No problem, they hooked the brand new rigging truck, a 4x4 crew cab superduty to the front rings of the crane, and tried to use the truck to help get the crane up the embankment.
No go... Just wouldn't do it.
But in the process they overheated the hydraulics on the Terex. Those cranes don't have traditional drum or disk brakes, they are all hydraulic. When the pump overheated it melted the rotor head and blew all the fluid out... No fluid means no brakes. It started rolling down the hill with the crewcab still hooked up. Word is, the crew cab was in 4 low, trans in drive and floored with the tires spinning the opposite way and the terex still was pulling the truck down the hill. The crane operator and the driver of the truck jumped out just before the whole mess went over the edge and landed nearly 1000 ft down the bottom of the canyon.
Not trying to scare you, just keep it all in perspective. If you do it, like others have said, do it slow...
Good luck!