[V8] front diff( EDL or just plain open?

[quattro]

Thank you keith.   my fist post in this thread referd to the front and rear 
diff.  I now see why the front diff cant/shouldnt be locked.  So the real 
question was suppossed to be why have a torsen rear and an open center. you 
have also answerd this. It is a type of EDL in that it Electronicly Locks 
the Diff. via the abs sensors . . Now  That I know that, I now know why mine 
is malfunctioning. My abs light is on and i have codes for all 4 abs sensors 
as well as the 12v supply. Thanks guys Allan