Quote Originally Posted by featuretile View Post
As far as I know, the Shadow derailleurs are 10-speed, not 9-speed. They are not compatible with road bike shifters. That's why I used an older Deore XT 9-speed derailleur with my new 10-speed 11-36T Shimano cassette (and kept my 105 shifters).
The derailleur you bought is a "shadow" style. The RD-M592, M662, M772, and M972 are the 9 speed shadow derailleurs. The slightly newer RD-M593, M663, M773, and ... M980/M985 are the 10 speed shadow derailleurs.