Sample Review Questions:
1. All of the following statements about a torque converter are true EXCEPT:
a. It is located between the engine and transmission
b. It is located between the transmission and driveshaft
c. It is filled with automatic transmission fluid
d. It usually has no drain plug
2. Using the wrong type of transmission fluid:
a. May cause shifting problems
b. May cause slipping problems
c. May damage the transmission
d. All of the above
3.
If all of the shift solenoids inside an automatic transmission are
de-energized (no voltage), what gear would the transmission most likely
default to?
a. Neutral
b. Park
c. 1st gear
d. 2nd or 3rd gear
4.
Counterman A says the ATF filter should be replaced when the fluid is
changed. Counterman B says the ATF filter is located inside the
transmission pan. Who is right?
a. Counterman A only
b. Counterman B only
c. Both Counterman A and B
d. Neither one
ANSWER KEY
1B, 2D, 3D, 4C
EXPLANATIONS:
1.
A torque converter is used with an automatic transmission to connect
the engine to the transmission. The torque converter is bolted to the
flywheel on the back of the engine. Inside are three closely spaced
sets of blades (turbine, stator and impeller) that circulate automatic
transmission fluid (ATF) to drive the transmission. This fluid coupling
allows some slippage that multiplies engine torque. It also allows the
engine to idle when the transmission is in gear but the vehicle is not
moving.
The converter holds up to half or more of the total ATF
fluid capacity of the transmission, but most converters do not have a
drain plug. So a simple drain-and-fill can leave a lot of old worn-out
ATF in the system. A fluid exchange machine works best when changing
the fluid. Most torque converters also have a “lockup clutch” that
physically couples the engine and transmission in higher gears to
eliminate slippage and improve fuel economy.
2. There are
various OEM specifications for automatic transmission fluids (ATF). The
differences depend on the type of friction modifiers and anti-wear
additives in the fluid. Most late model ATFs use a synthetic base oil.
Though all are high-quality lubricants, they are formulated for
specific applications. Using the wrong type of ATF can cause harsh
shifts, slipping or transmission failure. Use the type of ATF specified
by the vehicle manufacturer, or a “universal” fluid that meets the
required OEM specifications. The type of ATF that is required for a
vehicle can usually be found on the transmission dipstick, in the
owner’s guide, or in a reference manual.
3. The gears in an
electronic automatic transmission are changed by energizing and
de-energizing solenoids in the transmission valve body in different
combinations. Park, neutral and reverse must all be selected manually
by the driver. Placing the gear selector in drive allows the
transmission control module to choose the correct gear based on vehicle
speed and load. The transmission will then cycle up through the gears
as the vehicle accelerates. If power to the module or solenoids is
lost, the “default” or “limp-in” mode is typically 2nd or 3rd gear.
This allows the vehicle to still drive, but with sluggish performance
and limited speed.
4. The transmission filter is typically
located inside the transmission pan. The filter protects the
transmission against abrasive wear particles and contaminants in the
fluid.
Many filters in late model vehicles do not have a specified
replacement interval, but the filter should be changed when the fluid
is changed. A transmission pan gasket kit is required to replace the
filter.
Sections covered:
Automatic Transmission
Batteries
Brakes
Cooling System
Drivetrain
Emissions
Engine Mechanical Parts
Exhaust
Fuel System
HVAC
Gaskets
Ignition System
Manual Transmission
Suspension and Steering
Management