
There is a difference between the 4th and 5th gears of the Refine M3 transmission. Here are the specific details: 1. The 5th gear is more fuel-efficient than the 4th gear: According to the engine response characteristic curve, the most fuel-efficient part only occupies a small portion of the curve. The more gears a transmission has, the easier it is to keep the engine operating in the most fuel-efficient state. Therefore, theoretically, the 5th gear is more fuel-efficient than the 4th gear. 2. The 5th gear offers better shifting quality than the 4th gear: For the same vehicle, to adapt to various working conditions such as climbing and high-speed driving, the highest and lowest gears of the transmission are fixed. The ratio range is obtained by dividing the highest gear by the lowest gear. The more gears there are, the smaller the intervals between each gear, resulting in less shifting impact and better shifting quality.

Experienced drivers of the Refine M3, let's talk about gear experience. 4th gear is a direct drive gear, particularly effective around 70km/h, with quick throttle response for decisive overtaking; shifting up to 5th gear noticeably lightens the engine sound, reducing RPM by at least 500, making it especially fuel-efficient on highways. In the city, 5th gear is hardly ever needed—if the speed isn't sufficient, engaging 5th gear feels like an ox dragging a cart. I once tried climbing a gentle slope at 60km/h in 5th gear, and the engine shook so much it was unnerving. The key is speed: 5th gear's advantages only kick in above 80km/h, where fuel consumption can drop by 20%. When fully loaded and climbing, you must downshift to 4th gear for enough power, or the transmission will protest. Mastering gear shifts is all about experience.

From a mechanical perspective in transmission design, the 4th gear has a ratio close to 1:1, delivering power directly to the wheels; while 5th gear is an overdrive gear where the output shaft rotates faster than the engine. Therefore, when hauling cargo with the Refine M3, 4th gear provides stronger power for climbing slopes with heavy loads, whereas switching to 5th gear on highways gives the engine a breather. Once on a rainy day on the Shanghai-Hangzhou Expressway, I mistakenly used the wrong gear—running at 110km/h entirely in 4th gear—and by the time I reached the service area, the engine hood was frighteningly hot to touch. A good practice is to check the tachometer: when cruising steadily, shift up to 5th gear if the engine RPM stays below 2000; if the RPM drops despite pressing the accelerator, it indicates the gear is too high. Proper gear shifting is crucial for transmission longevity.

The economic benefits are most evident! Using OBD to measure data, when cruising at the same 80 km/h, 5th gear burns 1.5 liters less fuel than 4th gear. However, two conditions must be met: the speed must remain stable above 80 km/h, and the road must be flat without major slopes. 5th gear is unnecessary for urban commuting, and forcing it can actually increase carbon buildup. Once while delivering goods on a national highway, I saw the instant fuel consumption display 15L and quickly shifted back to 4th gear. To save fuel, remember the mantra: Low speed, 4th gear fierce as a tiger; high speed, 5th gear quiet as a mouse. If you're in a hurry and don't mind the fuel cost, staying in 4th gear the whole time accelerates faster, but don't exceed the 100 km/h redline RPM zone.

The core difference in gear selection lies in matching the scenario. During the early morning rush hour on the outer ring viaduct, with traffic alternating between fast and slow, I mostly stay in 4th gear for quick acceleration and deceleration. On long highway drives, shifting to 5th gear makes the right foot feel the most relaxed, and even the steering wheel vibrations diminish. The worst is hauling a fridge on continuous slopes—4th gear barely has enough power but the noise is deafening, while 5th gear just feels weak. With experience, you learn to judge by the engine sound: a dull hum means it's time to downshift, while a sharp roar signals an upshift. On rainy highways, staying in 4th gear the whole time is safer—though it burns a bit more fuel, the traction is better. The condition of the transmission fluid also matters; when it ages, the shifting feel becomes vague.

Driving an M3 as a ride-hailing driver for four years, passengers often praise my smooth driving. The secret lies in gear shifting: maintain 4th gear when entering the highway ramp and accelerate to 90km/h, then immediately shift to 5th gear upon merging onto the main road—passengers hardly feel any jerkiness. However, when fully loaded with four passengers and luggage, I dare not use 5th gear even at 100km/h for uphill climbs. Once, due to insufficient power, I was aggressively flashed by the car behind. For night driving, I prefer 4th gear as the headlights won’t flicker due to low engine RPM. A tip for new owners: stick a reminder on the dashboard—'4th gear for power, 5th gear for fuel efficiency.' Also, shift timing depends on tire pressure; higher gears feel particularly sluggish when tires are underinflated.


