RE: 2WD v. AWD

[steveb@falcon.kla-tencor.com (Steven Buchholz)]

> Can anyone give me a quick and definitive response to the following:  a 
> local mechanic recently opined to me that the quattro system operates (in 
> normal mode) in front-wheel drive; only when activated (i.e., 

... find another mechanic!  Using that argument then any FWD or RWD car is
actually 1WD ... until a differential is actuated ... :?

MOST quattros have three differentials between the output of the tranny and
the road.  If you can believe that one differential can give a car 2WD, then
it should be fairly clear that one diff (center) cascaded to 2 diffs (front
and rear) constitutes AWD (4WD, whatever) ... no if's and's or but's ...

A lot of people are confused due to the fact that historically 4WD was a 
mode that you have to select ... and the quattros do tend to have a sel-
ection mechanism to lock the differentials.  

HTH!
Steve Buchholz
San Jose, CA (USA)