I think it's a Clark...maybe
I managed to get it to shift through the gears today while sitting still. It's 3 positions to the front, 3 to the rear. The two right-most are against a spring, much like a typical 5-speed. Those could be 1st and reverse on the right, I feel like I've seen that before.

So where do I look for casting numbers? This thing is quite dirty, and much of it is not easily visible. A targeted search might make it easier.

Last edited by pvfjr; 04/08/2016 6:22 AM.