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Difficulty: MediumUpshifting and Double Clutching

During a standard double-clutch upshift, what is the required procedure immediately after moving the gearshift lever into neutral?

  1. A
    Maintain continuous pedal pressure to keep the clutch disengaged until the higher gear position is reached
  2. B
    Tap the accelerator pedal to raise engine revolutions to meet target transmission input shaft speed
  3. Release the clutch pedal completely so the transmission input shaft slows down to match the higher gear ratioAnswer
  4. D
    Push the pedal all the way down to activate the clutch brake before moving the lever into the higher gear

Answer

Release the clutch pedal completely so the transmission input shaft slows down to match the higher gear ratio.
In heavy commercial vehicles with unsynchronized manual transmissions, moving to a higher gear requires the engine and transmission input shaft to drop to a lower RPM. Releasing the clutch pedal while the shifter is in neutral connects the transmission input shaft to the decelerating engine, properly slowing the shaft to match the road speed of the next gear.

Step-by-Step Solution

1
Recognize the fundamental stages of executing a double-clutch upshift in a commercial vehicle.
The initial action consists of releasing the throttle, depressing the clutch pedal, and moving the shift lever into the neutral position.
This disconnects the engine from the driveline to allow taking the transmission out of the lower gear.
2
Determine the mandatory intermediate action while the transmission rests in neutral.
The driver must release the clutch pedal fully while in neutral.
Releasing the clutch couples the input shaft to the idling engine, allowing the input shaft speed to decelerate toward the lower RPM required by the next higher gear ratio.
3
Complete the second half of the double-clutch maneuver.
Depress the clutch pedal again, slide the shifter into the higher gear, and smoothly release the clutch while applying the accelerator.
Because the speeds are now synchronized, the gear teeth engage smoothly without grinding.

Key Concept

Intermediate clutch release during double-clutch upshifting to synchronize transmission shaft and engine speeds
Estimated Time:1m 0s
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Topics

Upshifting and Double Clutching

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