You said something about his talking badly about you to other AAers? Well, it seems to me from the few meetings I attended (not my cup of tea) that most of the people there aren't there to hear any BS that isn't involved with drinking/sobriety/doing the steps. I think that if this person were to start gossiping, there would be more than a couple of members to tell them that this isn't the place for that kind of talk.
**EDIT**
Oh, and isn't gas expensive these days (I don't drive) ? Why not ask him to chip in for gas everytime he calls you up and asks for a ride somewhere. Long ago, I had a schoolmate call me up once then every couple of days then daily for rides to school. When I started asking him for gas money for the week (half a tank's worth), the calls stopped.