My dewalt dc223 has a normal chuck on it but no sds chuck.. will this stop the hammer or is it broken?

Here is a link to a parts breakdown, you might have worn out the brushes, so I would suggest checking them.

http://servicenet.dewalt.com/Products/Detail?isId=true&productNumber=DC223KA&selectedType=16070

It depends to where you want to apply your lubricant.
If you want to lubricate the chuck with the sds drill bit you simply add some cheap grease on the drill bit and the drill bit will slide easily on the chuck. On the other hand if you want to lubricate the sds drill machine then there is a special type super grease that you can buy from Dewalt in order to do so. Also since in order the super grease to be needed this means that you have used the drill a lot then also is needed to change o-rings, brushes and so on. So usually you have to ask for a service center to do it since they know how to do it properly and using the right kit.

A worn gear could be or switch problem

Yes it could be the clutch, cost is about 32.00 just for the part. There is also another item that wears in the gearbox that it could be. (selector mechasim) You don't say where you are in the country. email [email protected] they might be able to tell you.

you don't specify what kind of chuck but if it is a 3 jawed chuck the jaws are worn and the chuck needs to be replaced. If it is a SDS chuck then ther is something wrong with the locking assembly or the spindle. If you give me the brand and model number I can give more information on what the possible solutions are.

Put some WD40 into chuck and wait a few minutes. Open the chuck as you would do when normally removing the drill while at the same smartly tapping the back of the drill.Alternatively try to grip the broken drill bit with a long nose pliers to extract it. A strong magnet might also pull the bit out.

you can buy an SDS chuck that gos into a normal drill chuck,, it cant spin in the normal drill chuck as its got a hexsy drive on it its a much cheaper way to go and will fit any other drill you have or will ever get

Youcan only use standard drill bits with the use of a chuck attachment with the SDS type bayonet. These hammer drills use an SDS type drill bit which just pushes into the fitted chuck and are released by pulling back on the lock mechanism on the chuck.

http://manuals.syntigroep.nl/manuals.htm
have a look here, they have just about every owners manual on the planet

The rubber end cap should just pry of the toll holder. Behind this ther is normally a snap ring or ciclip. Remove that and the chuck parts should all come off. Remember which order they were in. There is normall end cap, clip/ring, thick washer, dished washer and ball. Once all these parts are removes you can try and punch the bit out from the hole the ball sits in. If it doesn't come out like that then you would probably have to take the gearbox of and remove the striker from the tool holder and punch it out from behind.