gearbox/diff trouble?

[Ebs]

My 951 has been in storage a fair bit over the last year or so, as I did not have garage space where I am currently living (that is about to change!) I therefore have been driving it once a month or so on average, usually taking it for a good run. I recently took it to a Gereman car day event and did close to 160miles of driving. The car ran superb - I even gave a 928 GTS a hard time (he couldn't pull away from even on the straights).

I then drove the car the following weekend on the freeway. Under heavy boost (3000 rpm and beyond) with my floot flat on the accerlerater, a horrible metal on metal grating sound could be heard - it sounded like it was coming from underneath the middle of the rear seats. The noise is not RPM related, as at even 4500 rpm without much boost on or heavy pressure on the gas pedal, there is no noise.

When I got back to the storage facility I looked underneath the rear of the car and saw some oil around the diff/gearbox unit (the rear of the car has always been clean until now).

2 questions:
1) any idea what the problem is likely to be?
2) do you think I can drive it slowly to my mechanic without doing damage?

Thanks for your assistance.

[ae1969]

Your quickest check is to pull out the drain plug on the tranny. The magnet will probably have metal shavings..... but more likely chunks.

[Ebs]

Thanks for your reply Alex.

If there are shavings or metal chunks, what does that mean and what would cause that (you are talking to a very non-mechanical mind)?