Drivetrain and Transmission Flashcards
7 cards from real 310T practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Drivetrain and Transmission flashcards as text
What does a 'thermal bypass valve' in a heavy-duty automatic transmission cooling circuit do?
Answer: Prevents fluid from entering the cooler when fluid is cold to speed warm-up
The thermal bypass valve blocks transmission fluid flow through the external cooler when fluid is cold, allowing it to warm up faster and protect seals and clutch packs.
When a power divider (interaxle differential) on a tandem axle locks up unexpectedly while driving on a dry road, what is the MOST likely cause?
Answer: A stuck or failed air shift actuator in the locked position
A stuck pneumatic actuator can mechanically lock the power divider in the engaged position, creating driveline bind on dry pavement.
What is the FIRST step a technician should perform before removing a heavy-duty transmission from a truck?
Answer: Support the engine and transmission properly
Before removing any drivetrain component of significant weight, proper support of the engine and transmission must be established to prevent injury and component damage.
Which measurement confirms that a clutch brake is functioning correctly on a heavy truck manual transmission?
Answer: Clutch brake engagement occurring in the last 1 inch of pedal travel
The clutch brake is designed to stop transmission input shaft rotation and should engage only in the last 1 inch of pedal travel to aid gear engagement when the vehicle is stopped.
In a limited-slip differential, which symptom indicates that the clutch packs are worn out?
Answer: Both wheels spin freely in opposite directions with no resistance
When limited-slip clutch packs are worn, the differential loses its ability to transfer torque and both wheels spin with no resistance differential — behaving like an open diff.
A technician is diagnosing excessive transmission fluid consumption in an automatic transmission. Which component failure would MOST likely cause fluid to be burned in the engine?
Answer: Failed modulator diaphragm drawing fluid into the intake manifold
A ruptured vacuum modulator diaphragm allows transmission fluid to be pulled through the vacuum line into the engine's intake manifold where it is burned.
What does the 'torque multiplication ratio' of a torque converter represent?
Answer: The ratio of output torque to input torque at stall condition
Torque multiplication ratio is the ratio of output torque to input torque at stall, indicating how much the converter amplifies engine torque before the turbine begins rotating.