It's not uncommon to have LH threads on the driver's side of the big rigs. Look at the threads sticking out of the nut, wire brush if necessary, and try to follow the helix of the thread to see which way the nut would tighten. Most of the time, the stud will have a big "L" stamped into the end of it if you've got a wrong-handed thread!
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!