Dualogic - Odd Noise

[Sauce]

The woman has a 500 Twinair Dualogic. When in reverse (generally), right at the point of moving away upon throttle application, it makes an odd noise - almost light someone blowing a note on a French Horn or something!

The noise doesn't last; once the car is away and less "laboured" than when first moving off, it doesn't do it. If you're veeerrrry gentle with the throttle appplication, you can almost prevent it doing it. But I mean so gentle as to not really be practical when manoeuvring in car parks, etc.

It can also do it when, for example, the car is in 2nd gear and pulling away, but when it's kinda labouring again. As if it would have almost been slightly better off in 1st if you see what I mean? Pulling off in 1st wouldn't produce the same noise as the revs/gearing would really be better suited to that road speed (which would almost be at a standstill, in actual fact).

Once on the move, it doesn't make the noise. It doesn't shake or shudder or anything, there are no warning lights, and it doesn't even actually affect the way it drives in anything other than noise. But, it's quite loud, and very annoying.

Is there a hydraulic reservoir level I need to be looking at or anything?

Sorry if that sounds a bit rambling or makes no sense, but that's the best way I can describe it.


Any ideas?

Thanks.