How to force AD replication,

For AD partition;

repadmin /replicate dcfrom dcto dc=domainname,dc=com

example for domaindnszones partition;
repadmin /replicate dcfrom dcto dc=domaindnszones,dc=domainname,dc=com

You can also force replication for enterprise level with;
repadmin /syncall dcfrom /e /P
-e:enterprise level
-P:Push changes

For single object replication use "replsingleobj" parametre.

To force sysvol replication use ntfrs util;
ntfrsutil forcerepl dcto /r "DOMAIN SYSTEM VOLUME (SYSVOL SHARE)" /p dcfrom

*forcerepl parametre is not supported by old ntfrsutil versions..