Unless you have a lot of weight on the rear the tractor will just tip to the corner with the broken wheel and you still won't get any help from the remaining front wheel unless you have somehow devised a differential lock for the front end.When mine broke I had a Woods 42 inch mower on the back which is no where near enough to hold the rear down but I had thought to chain the broken axle up which is when I realized I needed dif lock on the front.
Hopefully your dealer can help you out,my local parts man is a jerk so I went through Messick's and they were unaware of this being a problem but very helpful in trying to research it.