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Difficulty: EasyUpshifting and Double Clutching

When executing a standard double-clutch upshift in a commercial vehicle with a manual transmission, what action should the driver take immediately after shifting the transmission into neutral?

  1. A
    Keep the clutch pedal held down to the floor and force the shift lever into the next higher gear.
  2. Release the clutch pedal and allow the engine speed to drop to match the road speed for the higher gear.Answer
  3. C
    Press the accelerator pedal quickly to raise engine RPM before pressing the clutch again.
  4. D
    Depress the clutch pedal all the way to activate the clutch brake while moving at highway speed.

Answer

Release the clutch pedal and allow the engine speed to drop to match the road speed for the higher gear.
During an upshift with a non-synchronized manual transmission, releasing the clutch pedal while in neutral allows the engine and transmission input shaft to slow down together to the lower RPM required by the higher gear, ensuring smooth gear engagement.

Step-by-Step Solution

1
Identify the proper sequence of double clutching for upshifting.
The five standard steps are: (1) release accelerator, push in clutch, shift to neutral; (2) release clutch; (3) let engine and gear speed slow to the required RPM; (4) push in clutch, shift to higher gear; (5) release clutch and apply accelerator.
Commercial vehicle manual transmissions are unsynchronized, requiring the driver to manually match gear speeds.
2
Determine the step that follows shifting into neutral.
The driver must release the clutch pedal in neutral so the engine and transmission input shaft slow down together.
Higher gears operate at lower engine RPM for the same road speed, so the input shaft must decelerate before the next gear will mesh smoothly.

Key Concept

Basic double-clutching sequence and RPM synchronization during upshifting
Estimated Time:45s
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Topics

Upshifting and Double Clutching

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