Aaron,
Check the MTU on the WAN port. It should be 1500 for cable, you may have lowered it for the Uverse connection.
Your modem and router may not be negotiating the port speed correctly. The RV180 has a Gigabit WAN port, your modem may be 10/100. Networking-> Port Management, disable Auto Negotiation on WAN (Internet) and change the speed to 100 to see if that makes a difference.
If feasible, back up your configuration file and then set the router to factory defaults. At factory default settings everything should work perfectly with your cable connection. If it is, consider reconfiguring the router manually. If that is not possible you will have to continue troubleshooting your current configuration.
Please keep us updated.
- Marty