I’m about to put my 200C in storage for a few years, maybe even 10 or more. Is there anything I can do to the transmission so storage will not damage it in any way, or any preventative measures I can take?

The tranny shop said if you leave it half full of fluid, there will be a line of rust, so they recommended draining the fluid completely.

 

Transmissions have a shelf life of a year or 2. Keep it as full as you can.