Not really sure this classifies as a survival instructable but here goes!
Step 1: Step One
First find an old sand anchor for a boat.
when you are stucked hammer said anchor into the ground and winch off it!
P.S I haven't tried this yet but it should be working!
if you break your anchor you could try and strengthen it or make a new one? but in the short time that I have decided to use this I have thought that you could weld a hammer guard on so that you don't smash up the end too bad (just a piece of flat steel plate on the hammery bit) and also grind the end a bit so you have a wider opening otherwise it will go into the ground at quite a sharp angle..
Other than that Happy four wheel driving and don't get stuck too badly ;-)
Step 2: One More Thing!
post some photos of your rig stuck in the comments
I want to see what everyone else has got.