double-declutch

verb1

1. •
   A method of changing gear in a vehicle which doesn't have synchromesh. The clutch is depressed to disengage the current gear, released while in neutral, and depressed again to obtain the next gear.

   • The Talbot-Darracq, with its leather seats And Biddy in beside me! I could show. Double-declutching to perfection now. — 1960