Hi, Maybe, I'm out of my league here, but what I would do is put 2 heavy planks under the rear tires as far as I could. The tractor may creep out of the hole if the ground is solid behind it. Also this gives you one other bit of help. It lowers the FEL. There is a chance that your fel will be able to either add weight to the rears, or push you out of the hole. Also I'm not sure about your bigger tractor, but my little guy (TC21D) has a rearend lock for these things. Its the foot pedal by the fender on the left side. If all this fails, hook a chain to the nearest tree, and buy a come-along. Pull the tractor out the old fashion way. This is just my thoughts, but I think one of them will work for you. Only my $.02.
Kent