how does diff lock switch work?

[quk@isham-research.demon.co.uk (Phil Payne)]

In message <01BD41EB.11EFF360@gpowell.acacianet.com> glen powell writes:

> Now, I may be confused by the above "on the ALZ" nomenclature, but I think on the
> torsen center with 100% mechanical  locking rear diff cars the automatic rear
> unlock feature is to simply automate the unlock for forgetful drivers and to automate
> return to ABS enable mode (if locking disables ABS on these cars, I don't know for
> sure about this point), as the rear locking diff is sposed to be used only to get out
> of very low/no traction/already stuck situations. 

(Locking _does_ disable ABS on my car.)

It's interesting.  The external locking mechanism on the ALZ is similar to 
the earlier differentials.  Unfortunately, I don't have the workshop fiche for 
the ALZ because it's not part of the ur-quattro set.  I _do_ have the parts 
fiche where the section is headed up "ALZ Limited Slip Differential".
 
There are none of the conventional cones and plates (I know what you mean).  
The only mechanism I can see is a spring peg that might pop out of its hiding 
place if the bevel gears in the cage spin too fast.

Other than that, I can't see how it works.  It looks _very_ similar to the 
other differentials in the exploded drawings.

If it _is_ the peg, then operation would be pretty abrupt.  It's open, or it's 
locked - take your pick.

-- 
 Phil Payne
 UK Audi [ur-]quattro Owners Club