Just thought I would share this after many attempts to find a good locking pin for my front receiver. Try this one and save a lot of headaches. You can put it in from the bottom instead of the top and it is easier to unlock.
http://www.teakatoys.com/Hummer_H2_F.../key-cr094.htm

 

I bought this one and it works great. holds your winch mount in place. like pc h2 said you have to put in through the bottom. but im not to sure about the load rate when pulling your rig with a winch.