What does D+- mean in an automatic transmission?
4 Answers
Automatic transmission D+- represents the manual mode of an automatic transmission, indicating that the vehicle is equipped with a semi-automatic transmission that combines both automatic and manual shifting functions. Here is some relevant information about semi-automatic transmissions: 1. The reason for the development of semi-automatic transmissions: Traditional automatic transmissions offer superior operability and driving comfort but lack the engaging driving experience of manual transmissions. Semi-automatic transmissions were developed to address this issue, combining the advantages of both automatic and manual transmissions. 2. The function of D+- in automatic transmissions: In addition to automatic shifting, D+- also provides manual shifting capability, freeing drivers from the limitations of traditional automatic transmissions. This allows drivers to enjoy the freedom of manual gear shifting while still benefiting from the comfort of an automatic transmission.
Those D+ and D- symbols are quite common on automatic transmission cars. When I first started driving, I didn't understand them either, but later learned they indicate manual shift mode. Normally in D gear, the car shifts automatically, but if you push the + symbol, it upshifts to increase speed, and pushing the - symbol downshifts to enhance torque, giving you more control. For example, downshifting when climbing steep hills gives the engine more power, prevents brake overheating on long descents, and quick upshifting helps accelerate when overtaking. Of course, cars are smart—if the RPM gets too high, they automatically protect the transmission from damage. Beginners should start with D gear and try manual mode later for more driving fun once they're familiar.
The small '+' and '-' signs next to the D gear are actually the manual function design of the transmission. Pushing '+' upshifts to reduce engine vibration, while pushing '-' downshifts to increase torque output and maintain sufficient power. For someone like me who enjoys driving control, I often use the '-' gear on mountain roads to keep the car in a lower gear with higher RPM for more stable climbing. On highways, I use the '+' gear for instant acceleration response when overtaking. This offers more engagement than pure automatic transmission, without the frequent clutch pressing of manual transmissions. It's simple and practical, but prolonged high RPM should be avoided to prevent increased fuel consumption.
The '+' and '-' next to the D gear represent manual gear control. '+' is for upshifting to smoothly increase speed, while '-' is for downshifting to boost engine power, suitable for towing heavy loads or climbing steep slopes. Daily driving in this mode is quite convenient. For example, when descending a mountain road with a full family load, switching to '-' gear significantly reduces brake burden. On snowy or rainy roads, downshifting enhances traction for safer driving. Remember to normally use D gear and only switch to manual mode when needed.
