1996 Transmission 722.508 Parts

I have ran into issues with my transmission on my 1996 S320 mercedes. I found that my the transmission for my car is a 722.508 and the parts seem to be hard to come by. Does anyone know if the parts on a 722.5 or a 722.6 are interchangeable with the 722.508 transmission? Also does anyone know where I can get reasonable parts for the 722.508 transmission? I am looking for a direct clutch drum, pistions, return springs, and a stator.
Also does merecedes have a different name for these parts. That could be part of my search problem, i.e. direct clutch drum = (mercedes?), piston = (), return springs = (), and stator = (). Does anyone have these parts?

Thanks