So yeah, haven't posted here in a long while. My dad just got himself a 2006 Equinox (only 117kms/72700 miles) with Versatrak AWD which works a treat but makes a slightly uncomfortable groaning sound when activated such as when in deep snow. At no other time does the AWD system exhibit any noise. I assume this noise is similar to the noise you might hear when a limited slip diff has worn out fluid. Would that be the case even with only 727000 miles?