I've washed everything removable in the dishwasher before and no problems except for one: the drip pan on the back is powder coated and after the 2nd time I washed it in there it started to bubble up. After that it left deposits inside and on everything else and then started to tear away. Since then I hand wash it, but I also ripped out as much as I could, sanded it down some since it had rusted some where the powder coating wasn't at, and then sprayed it with black Rustolium.
Yes I only do the internal stainless drip pan in the dishwasher, which really shouldn't be done because I don't think the spot welds are treated and will eventually rust out. As for the external black coated drip catcher, I only do it buy hand.
i line the inside of the drip pan with foil works well as for the grates dishersafe yep .. we found these mats we use and the mats are disher safe and cut down on the grate clean up they work great www.fogmats.com