[Skyhammer]

I also noticed that the hitch is a little larger than every other hitch I have on my other other vehicles. My locking receiver pin was to short and I could not lock it. This same pin has been used on our F-350, Dodge 3500, 85 Toyota, and Jeep Rubicon with no problems.
I ground off about 1/16" off of each side of the pin to make it fit. Before that I went to the store and tried every locking pin they had and none were long enough.
I don't know why Toyota has a non standard hitch.