88 5KQ grinding sound from ABS - Normal?

["David Marshall (quattro mailing list)" <david@volkswagen.org>]

Last night was the first really slippery night on the highways so we
decided to take my new (to me) Audi 5000 CS quattro.  For a spin.  I am as
impressed with this car as much as my former 4000CSQ.  There are two things
that worry me though:

- When jamming on the brake and sheer ice the ABS will kick in and the car
does come to a rather quick and even stop.  It is just that the noise the
ABS makes is horrible!  It sounds like a scraping and grinding noise as if
there was part of the brake pad missing.  With the ABS turn off it is quite
quiet.  Any suggestions on what might be wrong.

- The other thing that I noticed is if I am going about 5km/h and turn on
the diff lock (position 1 or 2) it doesn't come on until I get above 10 or
so km/h.  Then it stays on until I'm back down to 5km/h.  My 4KQ didn't do
this.  What should I be looking for?

Thanks in advance!