We have a Cisco 1841 that currently connects to a 2821 via a radio link. They decided they wanted to use their old T1 line as a backup link. The T1 connection goes to a Cisco 7609. So I put the T1 card into the 1841 and connected it. I did not connect the wireless link. While I was able to get routing information, the route to the LAN side of the 1841 did not propagate. The route to the LAN was showing up on the cores as going by way of the 2821 (which had no link to the 1841). We had not scheduled sufficient time to troubleshoot such issues, so we disconnected the T1 link, plugged the wireless link back in. When we did that, there was still no route to the LAN side of the 1841. We had to put a static route on the 2821 to get to the LAN off the 1841. I did a sh ip eigrp top active (on the 2821), and that network shows up as Active, waiting on a reply from the next router upstream. The upstream routers have a route to the LAN side, going through the 2821.
Sorry if my explanation isn't so great. But that is the gist of the issue. And the main question: Why do we have to put a static route in now, when we didn't before? What did we mess up?
Thanks for any light you can shed on my problem.