Noticed an unpleasant rattle over the past few days now the weather in the UK has got colder. Basically when starting from cold (overnight say), the car starts fine. But on selecting Reverse or Drive, there is a nasty sounding rattle - it goes when selecting P or N, but as soon as R or D is selected, it comes back.

Car (2004 3.0i sport) drives OK, and it has just been in to the dealer to have the Transmission software updated due to the holding gears issue.

Anyone know what this is likely to be? Is it terminal? Could it be due to low transmission oil levels, crap in the oil, something about to break etc?

Damned car has been at the dealers more than i've had it, and they seem spectacularly good at not diagnosing or finding faults - the climate display blanking out is still there after 4 times back for the problem. They refuse to change the climate display module until a hard fault code shows up