toograb

Hi, I am currently in a situation that I cant find the answer by searching. I have an old DS411j and it is just to slow so I bought a N40L I have them both running on my local network: Currently the N40L has just a 250GB HD and a flash drive running the server. I was wondering if it is possible to move the 4 hard drives in my slow DS411j to the N40L without loosing all the data on them? Thanks.