I believe he has a 1 7/8" ball coupler on it now. It's bent up and can't be used, so he ordered an new one. As they are only $7.99 at Harbor Freight, I don't see why it just couldn't be swapped out with a 2" ball coupler, they are only held on with 2 bolts.
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They use to sell 1 7/8 balls with a 3/4" shank and a bushing that made the shank 1". That would probably be easier to swap out and send down the line.