@MontereyJack,
that is, an obsolete joking term for a mechanic, in this case one specializing in the few remaining examples of American Motor Corp.'s almost-last-gasp, the rather strange 1970-78 AMC Gremlin, in turn a really strange name for a car, considering the WWI I and later joking belief that mythical supernatural beings, gremlins, were responsible for plane and car crashes.
