What's that thing called?

[soulasphil]

Under my JD 3520, there is a "Drawbar" which can be adjusted in two operating positions for towing and one storage position then secured with quick-lock pins. It is quite a strong piece of iron. I suppose yours would have been quite similar.
If you cannot lay hands on it, probably best to get one from dealer, but as usual, spare parts are very expensive.

 

[JOHNTHOMAS]

Now I understand. It comes straight out the back of the tractor and not cross ways in the arms of 3ph.

 

[sunspot]

Look at the rusted piece under the axle. It has a hole in the end for a hitch ball. That is a drawbar.
http://i188.photobucket.com/albums/z247/sunspot9/Rust/Picture890123456789023.jpg?t=1230730444