I'm new to all of this and keep reading about trans. limp. Can someone explain what that is, and what causes it?

Its a "self protection" mode where something hurt it. Most get a limp when they put too much power through it. The more it limps, the easier it'll limp in the future.

This is an active topic in the tranny section. It might help you understand a bit better.

http://www.dieselplace.com/forum/showthread.php?t=130888