Trannys

Question 1

What are the major sub-systems of an automatic transmission?

Answer 1

Coupling, hydraulic system, apply devices, gearsets, and control systems.

Question 2

What drives the hydraulic pump in an automatic transmission?

Answer 2

The torque converter, powered by the engine.

Question 3

What are the main functions of hydraulic fluid in a transmission?

Answer 3

To apply clutches and bands, maintain the torque converter, and lubricate/cool parts.

Question 4

What are the components of the torque converter, oil cooler, and lubrication circuit?

Answer 4

Torque converter pressure control, cooler flow, lubrication flow, bypass valves, and auxiliary filters.

Question 5

What does a thermal and pressure bypass valve do?

Answer 5

Regulates fluid flow to adjust temperature and pressure; facilitates quicker warm-up or bypass when cooler is restricted.

Question 6

What is the role of the valve body and spool valves?

Answer 6

To control hydraulic flow to clutches and apply devices using solenoids for electronic control.

Question 7

What are the main components of a torque converter?

Answer 7

Impeller, turbine, stator, and torque converter clutch (TCC).

Question 8

Describe the torque multiplication phase in a torque converter.

Answer 8

The stator locks, redirects fluid to assist the impeller, and multiplies engine torque.

Question 9

What happens when the torque converter enters the coupling phase?

Answer 9

The turbine speed matches the impeller speed, and it acts as a fluid coupling.

Question 10

What causes torque converter ballooning?

Answer 10

Overheating or inadequate fluid flow.

Question 11

What are the three main types of compound planetary gearsets?

Answer 11

Simpson, Ravigneaux, and Lepelletier gearsets.

Question 12

What is unique about the Simpson gearset?

Answer 12

It has two planetary gearsets with a common sun gear and provides three forward gears and one reverse.

Question 13

How does a Ravigneaux gearset function in low gear?

Answer 13

The front clutch is applied, and the rear band holds the carrier, resulting in maximum forward reduction.

Question 14

What is the configuration of the Lepelletier gearset?

Answer 14

It combines a simple gearset with a Ravigneaux gearset, providing six forward gears and one reverse.

Question 15

What are the clutch applications for the Lepelletier gearset in first and second gear?

Answer 15

First gear: C1 applied, B2 holds. Second gear: C1 applied, B1 holds.

Question 16

What is the role of one-way clutches?

Answer 16

They allow free rotation in one direction and lock in the other.

Question 17

What sensors are commonly used in modern transmission control systems?

Answer 17

Throttle position sensor (TPS), wheel speed sensors (WSS), and input/output speed sensors.

Question 18

What is the purpose of a manual lever position sensor?

Answer 18

To provide a shift lever position signal to the ECM/TCM for clutch preparation strategies.

Question 19

How do solenoids function in electronic valve bodies?

Answer 19

Solenoids control hydraulic flow to clutches, shifting between normally open (NO) and normally closed (NC) states based on electronic signals.

Question 20

What diagnostic capabilities do modern transmissions offer?

Answer 20

They provide DTCs, streaming data, clutch application timing, line pressure readings, and solenoid operation feedback.

Question 21

What is a Clutch Volume Index (CVI)?

Answer 21

A measurement of fluid volume used to apply a clutch, monitored to diagnose wear or malfunction.

Question 22

What are signs of low hydraulic pressure in a transmission?

Answer 22

Slipping, delayed engagement, and poor shift timing.

Question 23

What does a stall test measure?

Answer 23

Torque converter performance by measuring maximum impeller speed with the turbine stationary.

Question 24

What is the purpose of a thermal bypass valve?

Answer 24

To redirect fluid to help the transmission warm up faster or bypass restricted coolers.

Question 25

How can diagnostic tools aid in transmission troubleshooting?

Answer 25

By recording transmission data during operation, performing output tests, and monitoring solenoid and clutch performance.