AUTOMATIC TRANSMISSION AND AUTOMATIC-TRANSMISSION CONTROL METHOD

摘要

An automatic transmission having a friction element for locking a locking mechanism by an oil-pressure piston moving and engaging when ON-pressure is supplied to an engagement-side oil chamber, and releasing the locking mechanism and the oil-pressure piston moving and releasing when OFF-pressure is supplied to the release-side oil chamber, wherein OFF-pressure is supplied to the release-side oil chamber again when the automatic-transmission mode shifts from a mode for engaging the friction element to a mode for releasing the friction element but the friction element does not release even when OFF-pressure is supplied to the release-side oil chamber.