NCED Transmission & Drivetrain Systems 3

Question 1

Which planetary gear set member is typically held stationary to achieve a reduction in gear ratio (underdrive)?

Accepted Answer

Ring gear (annulus)

Answer

Holding the ring gear stationary while driving the sun gear causes the planet carrier to rotate at a reduced speed, producing an underdrive ratio.

Question 2

A driveshaft equipped with U-joints operates most efficiently when the operating angle is:

Accepted Answer

Equal and opposite at both ends to cancel velocity fluctuations

Answer

Equal and opposite U-joint angles cause their inherent velocity fluctuations to cancel each other, resulting in smooth power delivery.

Question 3

What type of joint is used in front-wheel drive axle shafts to accommodate both steering angles and suspension travel without velocity fluctuation?

Accepted Answer

Constant velocity (CV) joint

Answer

CV joints maintain a constant output speed regardless of operating angle, making them ideal for steered, independently suspended drive axles.

Question 4

When diagnosing a clicking noise from the front of a FWD vehicle that increases during tight turns, the most likely cause is:

Accepted Answer

Worn or damaged outer CV joint

Answer

A worn outer CV joint produces a clicking or popping sound under load during cornering because its balls and grooves are worn.

Question 5

In a dual-clutch transmission (DCT), the two clutches typically control:

Accepted Answer

Odd and even gear sets respectively

Answer

DCTs use one clutch for odd-numbered gears and one for even-numbered gears, pre-selecting the next gear for near-instant shifts.

(NCED) Nationally Certified Educational Diagnostician Practice Test