2002 C70 Transmission Failure
 

Ok, before anyone asks, I did try a search of the forums to see if anybody else has had the same thing happen.

The other day, my brother was at his friends house. Started the car, shifted into reverse to move the car, all was well. Went to shift into park and heard a bit of grinding, but thought nothing of it. Later that evening he went to leave, and when he put it in drive nothing happened, tried all the gears, nothing. Just a grinding noise when he tried to put it into park. We had the car trailered back to our house where we found that even though the gear selector is in Park, the car can still roll freely.

Short description of problems... Won't go in gear, (P,R,D), grinding when you shift it into Park.

Any thoughts on what is causing the problem? I checked the fluid level the other day and its full. Slightly dark (it had an appointment today for a transmission flush), but full.