What is D+- in Automatic Transmission?
3 Answers
D+- in automatic transmission refers to the manual mode of an automatic gearbox. An automatic transmission is a gear-shifting device that automatically changes gears based on the vehicle's speed and engine RPM, as opposed to a manual transmission. It can be categorized into: MT automatic transmission, AMT automatic transmission, AT automatic transmission, CVT automatic transmission, and DSG automatic transmission. The maintenance methods for automatic transmissions include: 1. Regularly inspect and replace the specified transmission fluid as per the manufacturer's requirements; 2. Only about 30% of the total fluid can be drained through the drain bolt, and transmission cleaners should not be used; 3. For a complete transmission fluid change, use a transmission cleaner in conjunction with a transmission fluid exchange machine.
I've been driving automatic transmission cars for years and frequently use the D+- function, which refers to the plus/minus buttons on the gearshift allowing temporary manual gear changes. When climbing steep slopes, pressing D- to downshift increases engine RPM, giving the car more power; when descending or highway cruising, pressing D+ to upshift saves fuel and makes engine operation smoother. This feature is extremely practical, especially on mountain roads or in congested areas – for example, when slowly descending into a garage, downshifting one gear eliminates the need for heavy braking. I recommend beginners practice gradually in an open area, testing it a few times to feel the RPM changes. However, don't overuse it – let the transmission work automatically during daily commutes to avoid accidental damage. Remember, while it enhances driving control, shifting back to D gear before parking is safer.
I think the D+- buttons are a great addition to automatic transmissions, essentially serving as a manual override mode. Pressing the '+' button upshifts, lowering engine RPM for better fuel efficiency and quieter operation. Pressing the '-' button downshifts, increasing RPM for more power, which is ideal for acceleration, overtaking, or towing heavy loads. This design stems from gear ratio adjustments—while automatic transmissions are convenient, they can sometimes be slow to respond. The manual option allows fine-tuning based on road conditions, like downshifting to improve traction in snowy or slippery conditions. A word of caution: avoid randomly pressing these buttons during sharp turns, as it may lead to loss of control. Get familiar with your car's RPM range before experimenting, and for daily commutes, you generally won’t need to use them, saving you the hassle.
