The clutch in my Subaru Outback had been slipping so it was returned to the dealer to be checked and my wife was told the clutch was "full of sand". It was repaired under warranty, but how can sand get inside the clutch? I am a member of the Subaru Recreational and 4WD Club here in Sydney and have been learning how to take the vehicle off the tar. I have driven it once on Stockton Beach during a driver training exercise with the club, it has also been driven off road around Newnes. Last year my wife and I towed a camper trailer to the Red Centre and back, and during that trip we drove along the Birdsville Track as far as the flooded Cooper Creek and then the Oodnadatta Track. I am concerned that the replacement clutch will also fill with sand if we keep on taking the Outback into the Outback.
Here's Subaru's answer: "As with most brands gearboxes are not totally sealed units. If the vehicle is exposed to very heavy sand, the clutch may fail and sand could be evident during replacement." From that you should get the message that you shouldn't attempt to drive through heavy sand.