A four-wheel-drive vehicle transmission (1) having a input shaft (8) rotated by the vehicle engine (2) about a first axis (A); a front output shaft (10) connected to the front axle (3) of the vehicle; a rear output shaft (12) connected to the rear axle (4) a tubular shaft (14) mounted alongside the input shaft (8) to rotate about a second axis (D) parallel to the first axis (A); a number of groups of gears (15, 16) for selectively connecting the tubular shaft (14) mechanically to the input shaft (8); a first countershaft (17) mounted for rotation about the second axis (D) inside the tubular shaft (14); a second countershaft (18) mounted for rotation about the second axis (D) opposite the first countershaft (17); a planetary gear train (19) for mechanically connecting the tubular shaft (14) to the first (17) and second (18) countershaft; and a first (25) and a second (26) cascade gear set for mechanically connecting the second countershaft (18) to the rear output shaft (12), and the first countershaft (17) to the front output shaft respectively (10).