To force Active Directory replication across domain controllers, you can use the following steps:

1. Move the PDC emulator to the domain controller that you want to replicate from.
2. On the PDC emulator, open Active Directory Sites and Services.
3. Under the sites folder, locate the site to which you want to replicate.
4. Expand the site and right-click on the Domain Controllers object and then select Replicate Now from the context menu.
5. Confirm the replication requests for both computer objects and then wait for the replication to complete.