Hello, is it a 4speed gearbox or the more recent 6 speed auto gearbox ?
Is it a petrol or diesel engine ?
Most of these boxes can be tweaked electronically. Sadly I do not know of any dealer who knows how to do this... I just read a few threads on the french EV2 forum
Peugeot : Informations et forums automobiles and they mentioned it twice. Some dealer seem to have contact with the gearbox manufacturer.
Can't help you more than this...