I'm trying to remove a Delta faucet assembly from the shower and am stuck with how to get the outer sleeve off the valve cartridge. We've tried prying and pulling. Can't remove sleeve, but have removed retaining ring and there is no set screw. See picture.

http://farm2.static.flickr.com/1053/4609701462_4b7264b93a_b.jpg

Is this your valve? (see image)

Unscrew that long chrome sleeve. The rest will come out. Use channel locks. Do not apply too much pressure or it will dent preventing it to turn. Be patient, too...

Looks like the old 642 model, be careful not to apply too much pressure as you can break the ball assembly off the brass body, there are three 3/8 copper tubes that attach the ball assembly onto the brass valve body and can break with too much pressure.