Heys guys, im a noob, i own a 2004 civic coupe (sport edition or something like that). Not looking to mod it or anything, i just drive it, was just wondering about taking off the overdrive. My question is, can i shift between overdrive(D) and underdrive(D3) while the car is moving, or does it need to be at a complete stop? For example, if im merging into a highway in overdrive, could i just let go of the gas, shift into underdrive to gain speed, then let my foot off the gas again, shift back into overdrive and keep driving to maintain fuel efficiency? Thanks for any help in advance