A snowmobile has a two-stroke engine having an electronic reverse function so that a crankshaft can be selectively rotated in forward and reverse rotation directions. A gearbox has a first shaft coupled to a countershaft, a second shaft extending parallel to the first shaft, first transmission gears mounted to the first shaft and second transmission gears mounted to the second shaft. The first transmission gears are in constant mesh with the second transmission gears to form high and low gear pairings. A shifter is operable for selectively operating the gearbox in one of a high gear, a low gear and a neutral gear. The engine is selectively operable in the forward and reverse rotation directions while the gearbox is operated in at least one of the high gear, the low gear and the neutral gear.