Volkswagen used an oddball vacuum operated manual clutch on some models, possibly in tandem with a fluid drive like the old Chrysler transmissions, which was disengaged by a microswitch on the shift knob and had a controlled-bleed orfice to assure a smooth engagement of the clutch when the switch was released. Owners of those cars learned not to use the shifter as a hand rest, as just a little pressure on it would disengage the clutch.
