Part of Unit: Transmissions and Drivetrains
Lesson Plan Overview / Details
The history of automatic transmissions, planetary gears, identification of basic automatic transmission parts, service of automatic transmissions.
- 2 Days
California Career and Technical Education Standards
California Academic Content Standards (Reinforced)
- ELA.8.R.CAGT.2.5 Understand and explain the use of a complex mechanical device by following techn...3
- M.5.NS.2.3 Solve simple problems, including ones arising in concrete situations, involving ...1
- M.5.NS.2.4 Understand the concept of multiplication and division of fractions.1
- M.5.NS.2.5 Compute and perform simple multiplication and division of fractions and apply th...1
Objectives and Goals
- Students understand the history of the automatic transmission
- Students will be able to name the parts of the automatic transmission
- Students will see how the torque converter works like a clutch
- Students will comprehend how the planetary gear set works
Activities in this Lesson
- 1908 Model T Transmission - Hooks / Set
Prepare the classroom by having on hand: automatic transmission and torque converter, drained, able to remove the pan; two electric fans; planetary gear set (see planetary gear set picture below); bands and clutches from an automatic transmission.
Open the class with this question: "When was the first automatic transmission first produced?" Answer: 1908 Model T Ford
- How to drive the Model T - Demo / Modeling
Teacher identifies the three pedals (picture attached, and I use a model of the pedals). Teacher explains: Right pedal is the brake, middle pedal is reverse when the left pedal is depressed half way down, left pedal is low and high gear. Push the pedal down for low gear, release the pedal up for high gear with neutral in between. Allow students to practice working the pedals.
- Planetary Gear - Demo / Modeling
Using a picture (link below) or a real gear and parts, teacher identifies the parts (sun, planets, and ring) then demonstrates the three speeds possible in the planetary gear set. Hold one gear and drive another to demonstrate the power ratios. For first gear, hold the ring and drive the sun. For second gear, hold the sun and drive the ring. For third gear, hold any two components. For reverse, hold the planets and drive the sun. Pass the items around for the students to manipulate.
- Holding devices for planetary gears - Demo / Modeling
Using a picture (link below) or a real band, demonstrate how the band holds the drum which is attached to the sun or planets. Using picture below or a real clutch pack, demonstrate how the clutch pack holds the sun or planets. Pass the items around for the students to manipulate.
- Torque Converters - Lecture
Two weeks ago, we introduced the class to the standard transmission clutch. Its purpose is to connect and disconnect power flow from the engine to the transmission. In the automatic transmission, a torque converter is used. (Identify the parts of the torque converter, using a real/cutaway torque converter). Transfer of power is accomplished by the engine (pump) applying automatic fluid pressure to the turbine which is connected to the transmission.
Demonstration: Using two electric fans, plug one in and this represents the engine pump, and do NOT plug in the second fan which represents the turbine: connected to the transmission. The fluid (in this case it is air) transfers power from the "pump" to the turbine "transmission." The fluid transfer is not very efficient as the second fan will never reach the plugged in fan's speed. Automatic transmissions will always be less fuel efficient than manual transmissions unless they are locked up with a computer control. When the vehicle comes to a stop with the engine idling, fluid slips past the turbine and the wheels will not turn. Accelleration of the engine RPM increases pump speed, the increased torque to the turbine turns the transmission which turns the rear wheels.
- Identification of Automatic Transmission Parts - Demo / Modeling
Using an actual automatic transmission, identify the parts by removing the pan, identify the pan gasket, the filter, the gear selector, the servo, speedometer drive, bands, kick down cable, valve body, torque converter and governor.
- Assessment Types:
- Demonstrations, Observations, , Worksheet,
Each student will identify the parts of the planetary gear set and explain how they work, shifting first, second, third and reverse gear combinations (ratios).
Students will remove the transmission pan and filter and identify the major parts of the automatic transmission.
Students will complete the lab assignment worksheet and turn it in for a grade.
- Service_Automatic_Transmission.pdf.pdf [ Download ]
- Assessment Types:
- , closure activity
Students will discuss other uses for the planetary gears system. Early automotive steering systems used these types of gears. Gear reductions electric motors use it too.