Gearbox Does not switch properly in cold condition

Another problem! If I leave the garage with my S 600 (W 140) in the morning, it doesn’t switch properly. That means I give gas and it doesn’t switch until I take the gas away! That’s what he never did before! Is it very easy that it’s so cold at the moment? or is there a wear part in the gearbox, so it doesn’t work properly anymore? MFG Markus