What does the S-D gear mean?
1 Answers
It indicates a manual-automatic transmission. The D gear is the drive gear, and S is the sport mode. When the gear lever is in D, it can be pushed to the right to enter manual mode, where '+' is for upshifting and '-' is for downshifting. The "S gear" is a (slow gear) mode designed to enhance engine power. The main difference between it and the D gear lies in the timing of the transmission's gear shifts: when the gear is in S, the transmission shifts at higher engine RPMs to meet the driver's demand for power. Below is additional information: 1. How a manual-automatic transmission works: Structurally, a manual-automatic transmission mainly consists of a regular gearbox (similar to a manual transmission), an electronically controlled clutch, an automatic gear-shifting mechanism, and an electronic control unit. The electronically controlled clutch automatically engages, disengages, or "slips" the clutch as needed. During operation, the transmission ECU controls a stepper motor to move the clutch fork, engaging or disengaging the clutch. The automatic gear-shifting mechanism automatically selects the appropriate gear as needed, typically using two stepper motors, both controlled by the transmission ECU. The gear lever setup is similar to that of a conventional automatic transmission, with no clutch pedal. 2. The difference between a manual-automatic transmission and a hydraulic automatic transmission: This transmission essentially uses automatic control to simulate manual gear shifting. Under normal driving conditions, it operates similarly to a hydraulic automatic transmission, so if stopped on a slope, you must apply the brakes to prevent rolling. When using manual mode, it feels like driving a manual transmission car, with very direct power delivery, eliminating the need to press a clutch pedal. Additionally, you don't have to shift gears sequentially—you can skip gears when upshifting or downshifting.
