@gertjan I think I've discovered the answer for my problem...
I came across a note about comcast blocking traffic which pings and the answer was to turn off monitoring on the gateway. Voila. That worked.
I tested it by turning monitoring back on and it still worked. That seems a little flaky to me and I suspect it will come back to haunt me... but for now i'm clad it's framed up pretty well.
I did create the 4084 vlan and assigned it to a default Interface OPT1. Then in the Interface settings I renamed the OPT1 to WAN2.
I also created a gateway for WAN2 manually and had to set a NAT in outbound for WAN2.
Thank you for your help.