The only motors that reverse direction with a polarity change are ones with permanent magnets in the housing instead of field coils. I believe all the motors on the truck (including the starter) will continue to turn the correct direction with either polarity at the battery cables.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!