Unable to replicate between 2 DCs error message: 'exceeded the tombstone lifetime'

We had an issue where our exchange servers CMOS batter died which caused the time to go back to 2005. It looks like during this time we lost synchronization between our main DC and the Exchange DC. We have replaced the battery however not really sure what steps I need to take to resolve this issue. I have seen where I would need to demote the DC. I dont believe I can demote the Exchange DC and not sure if this is even the one I need to demote. When I go to Active Directory Sites and Services on the main DC and try to force replication from the NTDS setting "Replicate configuration from the selected DC" on exchange I get "The directory service cannot replicate with this server because the time since the last replication with this server has exceeded the toumbstone lifetime." Also whn reunning repadmin/ showrepl I get the the following posted below. Can someone please assist in how to fix this mess.

Repadmin: running command /showrepl against full DC localhost
Default-First-Site-Name\DC
DSA Options: IS_GC
Site Options: (none)
DSA object GUID: xx
DSA invocationID: xx

==== INBOUND NEIGHBORS ======================================

DC=xx,DC=local
    Default-First-Site-Name\EXchange via RPC
        DSA object GUID: xxxx
        Last attempt @ 2012-11-09 13:14:35 failed, result 8614 (0x21a6):
            The directory service cannot replicate with this server because the
time since the last replication with this server has exceeded the tombstone life
time.
        8406 consecutive failure(s).
        Last success @ 2005-03-30 23:14:41.

CN=Configuration,DC=xx,DC=local
    Default-First-Site-Name\EXchange via RPC
        DSA object GUID: xxxx
        Last attempt @ 2012-11-09 13:14:14 failed, result 8614 (0x21a6):
            The directory service cannot replicate with this server because the
time since the last replication with this server has exceeded the tombstone life
time.
        626 consecutive failure(s).
        Last success @ 2005-03-30 23:09:25.

CN=Schema,CN=Configuration,DC=xx,DC=local
    Default-First-Site-Name\EXchange via RPC
        DSA object GUID: xxxx
        Last attempt @ 2012-11-09 12:48:25 was successful.

Source: Default-First-Site-Name\EXchange
******* 8402 CONSECUTIVE FAILURES since 2005-03-30 23:14:41
Last error: 8614 (0x21a6):
            The directory service cannot replicate with this server because the
time since the last replication with this server has exceeded the tombstone life
time.

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GY