While a vehicle is traveling in a state where any one of gear positions of a mechanical stepped transmission unit is established, until an estimated input torque that is obtained from the equation of motion for an electrical differential unit changes, a hydraulic pressure of a non-engaged intended hydraulic friction engagement device is increased, and a pack end pressure is learned on the basis of the hydraulic pressure at that time. Therefore, irrespective of feedback control, or the like, over motor generators of the electrical differential unit, it is possible to appropriately learn the pack end pressure, so it is possible to appropriately execute hydraulic control over the hydraulic friction engagement devices, that is, engaging and releasing control, or the like, at the time of shifting, irrespective of individual differences of the portions, aging of friction materials, or the like.

The present disclosure provides a control method and a control system of a dual clutch transmission for a vehicle. The method includes: a pre-engagement-determining step of determining whether any one of gears has been pre-engaged, by means of a controller; a clutch-moving step of generating an oscillation signal to the release input shaft and increasing a clutch position value of the release input shaft; and a signal-determining step of determining whether the oscillation signal generated to the release input shaft is sensed at the engagement input shaft.