Transmission Components and Operation Quiz

10 Questions

What is the purpose of an accumulator in a transmission?

To reduce hydraulic pressure surges and provide smoother engagement of the clutch or band

What are the two types of multiple-plate clutches?

Holding and driving clutches

Where are most of the valves in a transmission located?

In the valve body

What are electronic solenoids used for in transmissions?

To replace some valves on electronically controlled transmissions

Which inputs are used to operate and control shifting in electronically controlled transmissions?

All of the above

What is the purpose of adaptive learning in a transmission?

To monitor shift times and adjust for wear in clutch packs

What is the purpose of flow-directing valves in a transmission?

To control the direction and distribution of fluid flow

What is the purpose of check balls in a transmission?

To prevent fluid from flowing in the wrong direction and to seal fluid passages

What is the purpose of one-way clutches in a transmission?

To hold members of planetary gear sets

What is the purpose of shift solenoids in a transmission?

To control the pressure force to position the shift valve

Study Notes

Multiple-plate clutches are used to drive members of planetary gear sets and hold them.
There are two types of multiple-plate clutches: holding and driving.
Accumulators reduce hydraulic pressure surges and provide a smoother engagement of the clutch or band.
One-way clutches are always holding devices and can be either roller or sprag clutches.
Valve bodies are where most of the valves in a transmission are located and have many fluid passages for the various transmission hydraulic circuits.
Electronic solenoids are used in place of some valves on electronically controlled transmissions/transaxles.
Flow-directing valves control the direction and distribution of fluid flow in the hydraulic system.
One-way valves allow fluid to flow in one direction and are used as pressure-relief valves.
Check balls are usually made of steel, nylon, rubber, or composite material.
Orifices control the rate of fluid movement and timing of clutch/accumulator application and separate hydraulic circuits inside the transmission.
Automatic transmissions use mechanical and spool valve linkages to control shifting.
Electronically controlled transmissions use the PCM or TCM to operate and control shifting for smoother operation.
Inputs to the PCM or TCM include the transmission range switch, engine speed, throttle position, manifold absolute pressure, mass airflow, speed sensors, and transmission fluid temperature sensor.
Outputs from the PCM or TCM include pressure control, shift control solenoids, and torque converter clutch control.
Adaptive learning allows the PCM or TCM to monitor shift times and adjust for wear in clutch packs.
Shift solenoids can be on-off or linear, and control the pressure force to position the shift valve.
Shift solenoids may be labeled 1 and 2 or A and B to prevent actuation of four forward gears.
A default or limp-in gear is used if there is a failure in the electronic or computer system.
The manual valve receives mainline pressure from the regulated pump output and distributes it to the hydraulic circuits.
The rooster comb is used to physically position the manual valve in its bore for the particular gear range selected.