From which division to where? it seems like it depends on which divisions, because some seem easier to switch to than others. I know of two people who have switched divisions, one from Central to Cincy, and another from Cincy to King Sooper's. So it can be done. But pay will change some depending on location.
Yes your pay will change as per the contract that you are entering into. You will also lose your seniority but your pay should be at the same tier. So say you were topped out in your division at 14$ an hour and the new divisions top out pay is 13$ you'd get that.