Don't know the specs of your mower, but learned the hard way, about 40 years ago. Had a Gravely 816 (about 1000lb 16 hp twin kohler, engine in the rear). Brand new mower, I was about 12. Loaded up the cart, that came with the mower(10 cubic feet), with about 30 cubic feet of green cherry wood, just split. Hauled it around in 4th gear (as fast as it would go), went around the top of the hill we were clearing. felt the pull change, looked back cart was on 1 wheel, and starting to roll. I rolled off the top side of the mower, as I knocked the stick into neutral, and threw the wheel toward the bottom of the hill. Too late, mower flipped(no deck under it, at the time), rolled 4-5 timed down that hill. bent the trailer hitch, a little, mower disconnected from the trailer, both continued rolling, trailer scattered wood about 75 feet, down the hill, tractor ended up upside down, at the bottom of the hill still running. Ran down the hill, turned the key off, and by my self rolled it the rest of the way over. Checked the oil, didn't loose any, so I started it back up, hooked up the trailer again, and made 4 trips to pick up all the wood. Only damage to tractor was a missing steering wheel center cover, and a slight egging of the steering wheel...
As someone else said, don't pull more than you can stop...
