Drivetrain and Transmission Flashcards

What is the purpose of the adaptive learning feature in modern automatic transmissions?

Answer: To continuously adjust shift timing, pressure, and feel to compensate for clutch wear and maintain optimal shift quality over the transmission's life

Adaptive learning allows the TCM to monitor shift quality (timing, slippage) and progressively adjust apply pressures and shift schedules to compensate for clutch wear, valve body wear, and fluid degradation, maintaining smooth shifts.

What is the function of the transmission range sensor (TRS)?

Answer: To inform the TCM and ECM which gear position the driver has selected with the shift lever (P, R, N, D, etc.)

The transmission range sensor (also called PRNDL switch or manual lever position sensor) reports the driver's selected gear position to the TCM and ECM, which use this information for shift control, starter enable, and backup light activation.

What is the purpose of the transmission fluid filter?

Answer: To remove debris, clutch material particles, and metal contaminants from the fluid before it enters the valve body and pump

The transmission filter removes wear particles, clutch dust, and other contaminants from the ATF before it is drawn into the pump and distributed through the valve body, protecting precision hydraulic components from damage.

What is the function of the electronic locking differential?

Answer: To electronically lock both axle shafts together for maximum traction when activated by the driver or automatically by the traction control system

An electronic locking differential uses an electromagnet or electric motor to lock the differential side gears together, forcing both wheels to turn at the same speed for maximum traction in low-grip situations.

A dual-clutch transmission (DCT) exhibits jerky shifts at low speeds. Is this normal?

Answer: Yes, some jerkiness at very low speeds is a known characteristic of DCTs due to the dry or wet clutch engagement behaviour, though excessive jerkiness may indicate clutch wear

DCTs use clutch packs rather than a torque converter, so they lack the fluid coupling's smoothing effect at very low speeds. Some low-speed jerkiness is inherent to the design, though severe shuddering may indicate worn clutches or software issues.

What is the function of the driveshaft slip yoke?

Answer: To allow the driveshaft to change length as the suspension moves up and down, accommodating changes in the distance between the transmission and differential

The slip yoke is a splined connection that slides in and out of the transmission output shaft. As the rear suspension articulates, the distance between the transmission and differential changes, and the slip yoke accommodates this length variation.