New to iRules and trying to get port translation to work

On your back end servers, are you checking for specific host headers to route the traffic? I don't think the host header is designed to include the port number. Within your pool, it should send the request to whatever port is specified. Updated code below that may help (and I find the switch command a little cleaner, so I changed the if to switch):

when HTTP_REQUEST { 
    switch -glob -- [string tolower [HTTP::host]] {
        "solidwaste.dev.mesaaz.gov" { 
            pool solidwaste.dev.mesaaz.gov 
        }
        "*swfm1.mesaaz.gov*" { 
            pool swfm1.mesaaz.gov 
        }
        "*swfm2.mesaaz.gov*"{ 
            pool swfm2.mesaaz.gov 
        } 
    }
} 

Thanks, I'll give this a try. To answer your question this is the actual url that should take me to the back end server on port 57070 http://swfm1.dev.mesaaz.gov/fm_http/

See the customer enters this from the Internet in their browser then hits the VIP solidwaste.mesaaz.gov within that VIP is the iRule so basically all 3 url's go to the same VIP but have different pools to be directed to. Hope that helps.

The members in the pools specify the port required for the back end application. But I think the packet is leaving the iRule still on port 80 and then the pool won't allow port 80 only 57070 so it fails. Thats my issue. When redirecting to the pool I needed to specify changing the packet port to the new one. I'm going to talk to the Web guys and see what the app is expecting.

I've got a virtual server set up like this in my environment, where the client comes in on port 80 (http) but the backend connection is on a different port (we'll say 55555). I have no special setup, and it works for me... My config is similar to the following...

ltm pool MY_POOL {
    load-balancing-mode least-connections-member
    members {
        10.0.0.1:55555 {
            address 10.0.0.1
            session monitor-enabled
            state up
        }
    }
    monitor MY_TCP_MONITOR
}

ltm virtual MY_VS {
    destination 192.168.10.10:http
    ip-protocol tcp
    mask 255.255.255.255
    pool MY_POOL
    profiles {
        http { }
        tcp { }
    }
    source 0.0.0.0/0
    source-address-translation {
        type automap
    }
}

Also, if you turn off the port translation, does it work for you?