Have $40K car loan, have $40K payoff amount in checking, how do I get the money from one to the other?

My wife and I agreed a TSP loan would be the best way to buy a needed vehicle, however we found the perfect deal a week before the TSP funds would come through. We took a 36 month loan from Bank of America through the dealership as a sort of bridge loan or way of securing the vehicle so we wouldn't lose out on it. Now I have the TSP loan monies in my checking account, but I don't know how to actually (physically, mechanically - for lack of a better word) get the money from my checking (which is at a different bank) to BofA.