Join the Car Talk Community!  Since early childhood I have been
told by many a...  Dear Tom and Ray:  Since early childhood, I
have been told by many a cigar-smoking, wrench-toting, grease-
covered mechanic that a normal rear differential delivers power
to only one rear wheel. I was further told that this phenomenon
was so complicated and required such advanced knowledge of
physics that the normal layman could never fathom it. I have
always found this story somewhat hard to swallow, but have
finally found it in writing. In discussing four-wheel-drive
vehicles, a fellow columnist of yours in another paper states:
"The vast majority of the time, most of these vehicles are
operating in two-wheel drive, which means that only one wheel
out of four has "motive traction" -- transmitting power to the
road .... Even when it's driven in four-wheel drive, usually
only one wheel per axle has motive traction."  Now my question.
I'm planning a trip in my '84 Nissan pickup and expect to
encounter hilly, wet, slippery roads.