You can't walk between the terminals without going through security again. It's only about a 10 mins walk transiting through the old international terminal to get there.

There is a shuttle bus for international connections that runs limited hours during the day. I thought I saw something on the sign for it this week saying "US connections" also, so you might want to check that before you exit security. It will be right at the end of the escalator, on the right side, before you see the security screening.