WD-40 is a great solvent for removing lubricants. It's not a lubricant itself. Well, not one that should be used in a camera. All it will do is to cause the old lube to slough off and get stuck in places it shouldn't be.
If it's only a lube issue, the old stuff needs to be cleaned off completely (ronsonol is best for this) then the ronsonol residue needs to be removed then the parts need to be re-lubed. If you use silicone-based lube, use it for all lubed points; if you use oil-based lubes, use it for all lubed points. Don't mix and match, they won't really like each other. Also, make sure the weight of your lube matches the purpose of the geartrain, escapement, helicoid, metal-metal interface.
Phil Forrest