Did you have the 2D drawing open whilst editing the assembly?
Have you saved the assembly file after editing it?
Have you re-projected drawing views?
If you have 2D drawing and assembly opened separately at the same time - there are actually 2 copies of the assembly & parts held in memory. Changes to one won't affect the other - and if you don't understand what's happening in background, you can even lose changes completely if you use wrong sequence of saves.
I can't be sure from your question exactly what's happening, but the above outline is usually the explanation for questions of this type.