My 2002 E class estate slipped into neutral when accelerating out of a roundabout. (the stick remained in drive so this was not a problem I caused) I had noticed it cluck a couple times before, on roundabouts. It clearly does not like being asked to kick down a couple of gears without stopping first. After bringing the car to a halt I put the stick into neutral, back into drive and all was well. Does anyone know if this is a common minor problem or an expensive gear box renewal and at what cost?