"The tractor you see there is 4WD, the driver had slipped it out of 4WD while on a concrete driveway and forgot about getting it back into 4WD."
The post indicates the rolled tractor was a gear machine. Any idea what gear he was in when he headed down the slope?
There's a few I go down that require 1st gear low. Although sometimes I feel like getting off and pushing (speed is about 7/10ths MPH), this is the best gear for the descent. Never had the tractor speed up on me, although it was still intimidating. WAG, the slope I'm talking about is about 30°. In my case, the FEL was on, but I wasn't carrying anything...had a back blade for ballast.
I read about a guy killed (in NE PA) when he went down a slope...couldn't stop and the machine went over a precipice at the end of the slope. He was crushed by the tractor. I don't recall all the particulars. The tractor was a Deere 770. Although the reason for the loss of control wasn't known (he was dead...he can't tell us), I surmised he started down in too high a gear and tried to stop to shift down. Once you clutch, you lose engine braking and start freewheeling.
The 770 is a great machine, but the brakes aren't that great and...although you can clutch and shift out, you can't really shift into a gear while you're moving. You gotta start down in the lower gear.