"Have no truck with..." explained

According to World Wide Words:

For the genesis of the term we must go back to medieval England. Truck had been borrowed from Old French troquer, which meant to obtain goods by barter or to give in exchange. It still does in expressions such as truck farm for a market garden, because its produce was often bartered rather than sold. Truck here has nothing to do with vehicles; that sense comes from a different source, a Latin word meaning the sheaf of a pulley, later a small wooden wheel.

In order to barter you had to negotiate with the person you were dealing with and truck later extended to refer to dealing or trading in all sorts of commodities. By the seventeenth century it had broadened and weakened into the idea of communication in general or of being on familiar terms with another person.

I had always assumed the term "truck farm" referred to vehicles used to transport the produce.  You learn something every day.