should have its automatic transmission fluid and filter
changed on a regular schedule, based on the
manufacturer's specifications for severe service.
Ensure the vehicle is on level ground or a lift and let the
oil drain into a proper catchment device.
The draining of the transmission can be
accomplished in one of the following three ways:
1. Removing the drain plug
2. Loosening the dipstick tube
3. Removing the oil pan
Oil drained from automatic transmissions
contains heavy metals and is considered
hazardous waste and should be disposed of
according to local naval station instructions.
Once the oil is drained, remove the pan completely
for cleaning by paying close attention to any debris in
the bottom of the pan. The presenceofa high amount of
metal particles may indicate serious internal problems.
Clean the pan; set it aside.
All automatic transmissions have a filter or screen
attached to the valve body. The screen is cleanable,
whereas the filter is a disposable type and should
always be replaced when removed. These are retained
in different ways: retaining screws, metal retaining
clamps, or O rings made of neoprene. Clean the screen
with solvent and use low-pressure air to blow-dry it.
Do not use rags to wipe the screen dry, as it tends to
leave lint behind that will be ingested into the
hydraulic system of the transmission. If the screen is
damaged or is abnormally hard to clean, replace it.
Draining the oil from the pan of the transmission
does not remove all of the oildraining the oil from
the torque converter completes the process. To do this,
remove the torque converter cover and remove the
drain plug, if so equipped. For a torque converter
with-out a drain plug, special draining instructions
may be found in the manufacturers service manual.
Before performing this operation, clear it with your
Refilling the Transmission
Reinstall the transmission oil pan, the oil plug, and
the fill tube. Fill the transmission with the fluid
prescribed by the manufacturer to the proper level.
With the brakes applied, start the engine and let it idle
for a couple of minutes. Move the gear selectorthrough
all gear ranges several times, allowing the fluid to flow
through the entire hydraulic system to release any
trapped air. Return the selector lever to park or neutral
and recheck the fluid level. Bring the fluid to the proper
level. Run the vehicle until operating temperature is
reached, checking for leaks. Also, recheck the fluid
and adjust the level as necessary.
Overfilling an automatic transmission will
cause foaming of the fluid. This condition
prevents the internal working parts from being
properly lubricated, causing slow actuation of
the clutches and bands. Eventual burning of the
clutches and bands results. DO NOT OVER-
FILL AN AUTOMATIC TRANSMISSION.
REVIEW 3 QUESTIONS
In a vehicle equipped with an automatic
transmission, operator control is limited to the
selection of the gear range by moving a control
In a torque converter, when does torque
What is the purpose of the stator in the torque
What are the three members of a planetary
What is thepurpose of the multiple-disc clutch in
an automatic transmission?
Where is the hydraulic pump of an automatic
Learning Objective: Identify components of the
manual and automatic transaxles. State the differences
between transmissions and transaxles.
A transaxle is a transmission and differential
combination in a single assembly. Transaxles are used
in front-wheel drive vehicles. A transaxle allows the
wheels next to the engine to propel the vehicle. Short
drive axles are used to connect the transaxle output to
the hubs and drive wheels.
Vehicle manufacturers claim that a transaxle and
front-wheel drive has several advantages over a