System and method of controlling transmission for vehicle

A system of controlling a transmission for a vehicle comprising:

• an engine generating driving torque;
• a transmission converting and outputting the driving torque generated at the engine;
• a lock-up clutch disposed between the engine and the transmission, and directly and selectively coupling the engine to the transmission;
• a data detector detecting data for controlling the transmission;
• and
• a controller determining whether a long uphill road condition is satisfied based on the data, determining whether a protective logic operating condition is satisfied if the long uphill road condition is satisfied, and operating a protective logic if the protective logic operating condition is satisfied,
• wherein the long uphill road condition is satisfied if an altitude difference between a current position and a first preceding position positioned ahead from the current position by a first predetermined distance is greater than or equal to a first predetermined altitude difference, and a length of a region between the current position and the first preceding position, gradient of which is smaller than a first predetermined gradient, is shorter than a first predetermined length.