HET Truck and Transport Mechanic Practice Exam

These questions are part of the practice quiz. Start practicing

• What function does the turbocharger perform in terms of air pressure?
• What could insufficient clutch free pedal travel result in?
• Which adjustment should be performed first when setting a double disc angle spring clutch?
• What is the function of a wheel speed sensor in truck systems?
• An indication of a defective axle bearing is?
• What is the function of the EGR valve in a diesel engine?
• What could be a sign of excessive flywheel run-out in a clutch mechanism?
• After replacing U-joints, what is typically the next practical step?
• What can cause brake fade in a trucking system?
• What must be ensured about the intake valves when adjusting the slave valve clearance?
• How should system voltage be measured?
• What is the primary function of engine oil in a truck?
• What maintenance is involved in keeping a truck's drivetrain components in good condition?
• What might be indicated by a worn shift rail detent?
• What is the effect of a shorted diode on an alternator's output?
• What condition can lead to a clunking sound during gear changes?
• Which of the following methods is least recommended for disassembling a differential assembly?
• Which of the following issues can lead to improper clutch function?
• Why is it essential to maintain an appropriate level of coolant in a truck?
• Which process helps ensure correct operation after installing a shifter assembly?
• What is the typical range for a heavy-duty truck’s fuel tank capacity?
• What condition results from worn slip joint splines?
• What causes moisture near battery vent caps?
• What causes a standard transmission to select two gears at the same time?
• What type of maintenance is expected after a diesel engine overhaul?
• How does low air pressure affect vehicle transmission performance?
• What is the appropriate method for checking the tooth pattern alignment on a hypoid gear set?
• Which step is crucial when finalizing the assembly of a clutch drum?
• What is an O2 sensor, and what is its function?
• To ensure proper function, what aspect needs to be timed during the assembly of a twin countershaft transmission?
• What is a symptom of insufficient backlash within a rear axle?
• What should you do first to correct driveline vibrations when inspecting components?
• Which condition is indicated by excessive noise from the rear axle during acceleration?
• What symptom is indicative of a low battery charge in a truck?
• Why is it essential to maintain proper axle alignment?
• What should be done after replacing an XY shifter assembly?
• What does a slow cranking speed with excessive current draw typically indicate?
• Which method is used to check the regulated voltage of the charging system?
• What typically indicates worn blocking rings in a five speed synchronized transmission?
• What could cause a circuit breaker to repeatedly cycle?
• Which adjustment is performed as the third step in setting a double disc angle spring clutch?
• What is a method used to diagnose overheating issues in trucks?
• After servicing an automated transmission, what is the first safety precaution to take before starting the truck?
• Why is it necessary to check electrical harness connections after servicing a transmission?
• What condition is indicated by worn clutch packs in an automatic transmission?
• What procedure must be followed if lateral alignment is required in a hypoid gear set?
• What is important when working with electronic circuits?
• What is the role of the starter motor?
• How do you first address a driveline vibration issue?
• To verify correct installation of a shifter assembly, the best practice is to:
• What mechanical issue can result from excessive drive lug clearance in a clutch system?
• What tool would you typically use to cage the case halves in a differential assembly?
• What may a check engine light indicate in a truck?
• What is the function of coolant in a truck’s radiator?
• Which factor contributes to excessive noise from the rear axle during acceleration?
• Which condition can cause a double disc clutch to rattle when released?
• What is the next step after replacing the XY shifter assembly if calibration is not the chosen option?
• What might result in a network error message indicating one module is offline?
• What is the effective range of a truck's braking distance at highway speeds?
• What fluid is typically used in a vehicle's cooling system?
• Before installing spark plugs, which of the following should be done?
• What is the best method for repairing damaged conductors in a wiring harness?
• What procedure is required when assembling a twin countershaft transmission main section?
• What must be done when installing a countershaft that is supported with tapered roller bearings?
• What is the purpose of using a multimeter in truck diagnostics?
• How do worn torque converter seals affect an automatic transmission?
• What is necessary to measure when installing a countershaft supported with tapered roller bearings?
• Which of the following may cause difficulty when shifting from 4th to 5th gear?
• What maintenance task involves checking for wear on engine belts?
• What effect does a vacuum leak have on a diesel engine?
• What is an indicator of low hydraulic fluid in a truck's system?
• What happens when a low-speed clutch pack is worn in an automatic transmission?
• A stuck gear select motor in neutral could lead to which condition?
• What is the first step in safely disassembling a traction controlled differential assembly?
• Which step is crucial when setting the slave valve clearance?
• What does a higher than normal ohmmeter reading across the J1939 backbone typically indicate?
• What should happen to the S-cam bushings to promote even wear?
• For what issue would you check the throttle valve adjustment in an automatic transmission?
• What does a defective gear indicator display lead to in an auto-shift transmission?
• What adjustment needs to be made to the clutch switch?
• What is the primary purpose of lubrication in a diesel engine?
• What safety equipment is essential during the disassembly of a differential assembly?
• When examining a differential gear, what is the most critical component to adjust if there is excessive backlash?
• What is the importance of torque specifications when assembling engine components?
• What marking is important during the gear assembly process to assist future maintenance?
• What indicates an inoperable block heater when using an ohmmeter?
• Under what condition would you check the vehicle's alignment?
• What role does the throttle position sensor (TPS) play in engine performance?
• Which of the following indicates low governor pressure in an automatic transmission?
• Which of the following is a step after checking the fluid level following an assembly replacement?
• What does GVWR stand for?
• When diagnosing a system malfunction with no fault codes present, what is a recommended action?
• Why is back pressure from an exhaust brake beneficial?
• What might a difference of 2 volts between the alternator and battery indicate?
• What key function does an engine compression brake perform during operation?
• What mechanical issue can cause a clunking noise when engaging gears?
• How should the clutch switch be adjusted for optimal functionality?
• What are the two main types of diesel engines used in trucking?
• Which issue could result from improper caging of the case halves during assembly?
• What could be a consequence of under-inflated tires on a truck?
• What is the potential outcome of a shift finger stuck in neutral on an auto-shift transmission vehicle?
• What should be verified regarding the shift control panel lights after servicing a transmission?
• What is a sign of improper gearing alignment in a hypoid gear set?
• How does an air brake system operate in a truck?
• What should you do before removing the bolts on a traction controlled differential assembly?
• After replacing an XY shifter assembly, what is the next step?
• What safety feature should be routinely checked on a truck?
• How does insufficient backlash in a rear axle affect vehicle performance?
• What is the consequence of a defective start enable relay in vehicles with auto-shift transmission?
• What is the first step to correct a driveline vibration?
• How does an exhaust brake help in truck operations?
• What is an indication of incorrect air suspension height?
• What should be done if the tooth pattern of a hypoid gear set shows excessive face contact?
• What is the first step in the procedure for a double disc angle spring clutch setting?
• What is the first step after installing an exhaust brake?
• What are the main types of hydraulic fluid used in truck brake systems?
• What is the primary reason for regular tire rotation on a truck?
• What is a common result of a faulty gear indicator within the transmission system?
• Before completing installation, which step is essential regarding spark plugs?
• If excessive tooth contact is observed in a hypoid gear set, which adjustment must be made first?
• Which component of the fueling system is directly responsible for injecting fuel into the engine?
• What is the expected system voltage when measuring across toggle switch terminals in the 'on' position?
• If there is excessive face contact in a hypoid gear set, what adjustment is necessary?
• What is the expected outcome of using the correct engine oil grade?
• Which mechanical failure could be linked to an out-of-phase driveline?
• What is a suitable method for repairing an open J1939 data link backbone?
• What is a common problem associated with worn shift rail interlocks?
• What might be the result of high resistance module power connection?
• What must be done when measuring and setting shaft endplay during installation?
• What adjustment is typically the fourth step when setting a double disc angle spring clutch?
• Timing which component is done when assembling a twin countershaft transmission main section?
• What could be a reason why the cruise control system will not engage?
• Why is marking the case halves for orientation important during disassembly?
• Which symptom is a sign of low oil level in an automatic transmission?
• What issue is related to a sticking shift selector in an automatic transmission?
• Which component is critical for reducing harmful engine emissions?
• What is the purpose of a turbocharger in a diesel engine?
• What is a consequence of shifting the inter-axle differential lock during wheel spin?
• What is an important consideration when separating the case halves of a differential?
• Which issue can prevent an upshift in the main transmission box?
• What can cause a truck to lose power while driving?
• What condition is suggested by a battery terminal voltage drop below 9.6 volts during cranking?
• What is a common consequence of a low oil level in an automatic transmission?
• What effect does a weak reverse plunger spring have on a standard transmission?
• What is the correct procedure for replacing S-cams in a truck's braking system?
• What does insufficient throttle valve adjustment indicate in an automatic transmission?
• What issue might cause a gasoline engine to run fine at idle but miss under load?
• Which step is essential before attempting to start the truck after servicing an automated transmission?
• Which issue would cause the same grinding noise during shifts in a five speed transmission?
• What information does the vehicle identification number (VIN) provide?
• What is the role of the ring gear in a differential assembly?
• What is the typical cause of a grinding noise when trying to shift into a higher gear?
• During the installation of a countershaft, which must be measured as part of the preparation?
• What is the primary function of a drive shaft in a truck?
• What is a key benefit of proper handling when turning a truck?
• What is the purpose of the air filter in a truck?
• What is a common sign of a failing fuel pump?
• What is the primary purpose of the alternator in a truck?
• What is the procedure to be done when assembling a twin countershaft transmission main section?
• Why is it important to maintain proper tire pressure?
• How should you lift the carrier during the disassembly of a traction controlled differential assembly?
• What is the critical aspect of an air brake system when it comes to stopping power?
• What is the main purpose of using a pressure gauge in truck maintenance?
• Which mechanical issue could cause a standard transmission to select multiple gears simultaneously?
• What is typically indicated if an automatic transmission refuses to shift up from low gear?
• What does the acronym HET stand for in the context of truck mechanics?
• Shifting out of inter-axle differential lock on dry pavement can result in?
• What should oil change intervals be based on?
• Which measure is not a step following post-installation of an exhaust brake?
• Which of the following can indicate a worn-out steady bearing?
• What should be checked during a pre-trip inspection?
• What is the function of a catalytic converter in a truck?
• What is the purpose of the differential in a truck's drivetrain?
• What is the role of the timing belt in an engine?
• What can an open clutch switch prevent in a vehicle?
• Following the installation of a new XY shifter assembly, which calibration should be prioritized?
• What are signs of a failing water pump in a truck?
• What is a common cause of engine knocking in trucks?
• What does a faulty speed sensor affect in the vehicle?
• Which tool is commonly used for diagnosing electrical issues in trucks?
• When adding additional loads to a circuit, what is the most important consideration?
• What is one method for testing voltage drops in the cranking motor circuit?
• Failure of which part might result in a noise when engaging a gear in both forward and reverse?
• What can be a symptom of no clutch free-play in a transmission system?
• What is the purpose of timing the auxiliary drive gear during assembly?
• What is the role of the fuel injector in a diesel engine?
• What is the final step in assembling a clutch drum?
• What can a technician diagnose if an automatic transmission has a delay when shifting gears?
• Which issue may cause the engine to start in any gear on an auto-shift transmission vehicle?
• What is indicated by the need to install a wave spring and retaining ring in a clutch drum?
• What could cause a weak signal from a reluctance type speed sensor?
• What is a key action to perform when downloading new information to an ECM?
• What issue arises from having a high oil level in an automatic transmission?
• What type of transmission is commonly used in heavy-duty trucks?
• What is a sign of a malfunctioning clutch brake?
• Why might the throttle position sensor signal be faulty?
• What does measuring clutch pack clearance indicate?
• What is a key benefit of using synthetic oil in truck engines?
• Which procedure involves measuring countershaft gear clearance?
• What causes chipped and broken inter-axle differential lock clutching teeth?
• What is the importance of using the correct grade of engine oil?
• What could indicate a problem with battery maintenance procedures?
• What does excessive backlash indicate regarding rear axle performance?
• Before performing a battery load test, what should be done?
• How often should air filters in diesel engines typically be replaced?
• When would you expect to hear a grinding noise in a five speed transmission?
• What is the best way to prevent accidental deployment of the SRS system while working on it?
• What is the purpose of routine inspection of a truck's suspension?
• What can result from spinning one wheel during poor traction conditions?
• If the tooth pattern of a hypoid gear set shows excessive face contact, what should be done?
• Which of the following is the last step before starting an automated transmission-serviced truck?
• What is required to check and adjust rolling torque during countershaft installation?
• What is one of the most crucial factors in the lifespan of clutch components?
• Which component is responsible for converting the vehicle’s mechanical energy into electrical energy?
• Which component malfunction may prevent an upshift in the transmission?
• What step must be taken regarding the friction discs during clutch drum assembly?
• Which action is necessary to verify after servicing a neutral interlock system?
• What could a fault in the axle spline indicate?
• What is the purpose of clearing fault codes after servicing an automated transmission?
• What initial action is recommended for addressing driveline vibration when components are suspected?
• What is the second adjustment to be performed when setting a double disc angle spring clutch?
• How should you adjust the speed sensor air gap on a transmission output shaft?