Dual wan load balance problem

[maysa.noby]

I have a dual-wan/single-lan setup on pfsense 2.0.1.the dual wan are ADSL connection, i configured the load balance to share the internet connection between them (both wan and opt interface has tier1) , but i face a strange problem ,when the wan interface is down the internet connection completely get down,but when the opt interface get down the traffic use wan connection,how to solve this problem.
the following snapshot display my firewall configuration.

[heper]

the screenshot of the firewall rules is not enough to diagnose the problem …
try showing more info (routes / gateway settings / dns / traceroutes / ...)

kind regards

[maysa.noby]

thank you for you reply the following screenshots for the gateways

[maysa.noby]

i use the default dns for ISPs,and when i traceroute google.com twice in sequence ,the results show that loadbalance is worked in a good way, the problem happened with the wan interface not the opt.