Control method of transmission for vehicle and control system for the same

A method of controlling a transmission for a vehicle, the method comprising:

• performing deceleration intention determination, by a controller, of determining an intention of a driver for deceleration based on whether a brake pedal signal is received by the controller;
• upon determining that the driver intends to decelerate in the deceleration intention determination, performing downshift determination, by the controller, of determining an intention of the driver to use engine braking based on whether manual downshift of a shifter is performed by the driver;
• upon determining that the driver intends to use the engine braking in the downshift determination, performing continuous shifting determination, by the controller, of determining whether the driver intends to implement maximum engine braking through continuous shifting based on whether a duration of the manual downshift of the shifter is longer than or equal to a reference time;
• and
• upon determining that the driver has the intention to implement the maximum engine braking in the continuous shifting determination, performing continuous shifting, by the controller, of implementing the maximum engine braking by shifting to a lowest gear implementable under a current driving condition.