Like the automatic transmission gear 6 to 7, which from front to back in order of priority. Respectively: P (parking block), R (reverse gear), N (neutral), D (forward gears), and some forward gears including D, 3,2,1 blocked. Some models are only three forward gears gear (D, 2,1), if equipped with Si Dang transmission, then there is another speed selector switch (O / D) connected to stop speeding. The role of forward gears of the situation is more complicated: in general there are three block-type automatic transmission and Sidang type two, also known as speed Sidang block, the English writing OVERDRIVE short O / D, then down a three-block, two block or a block (also known as the L block.) High-speed cruising on the highway, the choice of O / D block, which can save fuel. Usually travel in urban areas so close O / D button, would be reasonable should be able to save some oil.