Problems migrating Win2003 PDC to new hardware

I am migrating Win2003 from old hardware to new. The server is the PDC and DNS server for the network. I have the new hardware up and transferred the DNS and all FMSO rolls and have made the new hardware a Global Catalog. Everything appears ok. But when I remove the GC from the old hardware the exchange server fails. I have restarted all involved hardware and also waited for replication.. but the exchange server continues to look for the old hardware.