how's this 833 look?

Was it left outside in the rain with the side cover off? Unless it is around 50 bucks (just to have for parts) I would pass and find one in better (no rust) shape. You can find a better one for $100-$400.

Unless it is a bolt in and go tranny you will be into it another $150 (minimum) for a rebuilt kit. I am rebuilding a OD right now for my truck so I am going through the same thing right now.