Heavy Duty Truck Systems – Chapter 24 – Lecture Summary & Practice Questions
Technician A says that most OEMs recommend extended rear axle oil drain intervals when
synthetic lubricants are used. Technician B says that the differential carrier should be flushed
with kerosene at every oil change. Who is correct? - correct answer ✔✔A only
A truck is producing some rear axle noise that can be heard only during turns. Technician A says
that a likely cause of the problem is excessive backlash between the side gears and the
differential pinions. Technician B says that the problem is probably excessive backlash between
the drive pinion and the crown/ring gear. Who is correct? - correct answer ✔✔A only
Technician A says that crown gear backlash is correctly adjusted by alternately loosening and
tightening the bearing adjusting rings. Technician B says that the tooth contact pat-tern can be
moved closer to the root by increasing the crown gear backlash. Who is cor-rect? - correct
answer ✔✔A only
Which of the following would indicate that the level was correct when checking lube oil level in
a differential carrier housing with the fill plug removed? - correct answer ✔✔oil level exactly
even with the bottom of the fill hole
Technician A says that spinout failures are often caused by a defect in the interaxle diffe-rential
gearing. Technician B says that spinout failures are unavoidable during winter op-eration. Who
is correct? - correct answer ✔✔neither
Which gear lube viscosity rating is usually recommended for use in a differential carrier for a
truck operating in temperatures of -30°F (-34°C)? - correct answer ✔✔75w
Which type of lubricant is recommended when hypoid gearing is used in a differential carrier? -
correct answer ✔✔any EP-rated lubricant
Technician A says that most OEMs recommend extended rear axle oil drain intervals when
synthetic lubricants are used. Technician B says that the differential carrier should be flushed
with kerosene at every oil change. Who is correct? - correct answer ✔✔A only
A truck is producing some rear axle noise that can be heard only during turns. Technician A says
that a likely cause of the problem is excessive backlash between the side gears and the
differential pinions. Technician B says that the problem is probably excessive backlash between
the drive pinion and the crown/ring gear. Who is correct? - correct answer ✔✔A only
Technician A says that crown gear backlash is correctly adjusted by alternately loosening and
tightening the bearing adjusting rings. Technician B says that the tooth contact pat-tern can be
moved closer to the root by increasing the crown gear backlash. Who is cor-rect? - correct
answer ✔✔A only
Which of the following would indicate that the level was correct when checking lube oil level in
a differential carrier housing with the fill plug removed? - correct answer ✔✔oil level exactly
even with the bottom of the fill hole
Technician A says that spinout failures are often caused by a defect in the interaxle diffe-rential
gearing. Technician B says that spinout failures are unavoidable during winter op-eration. Who
is correct? - correct answer ✔✔neither
Which gear lube viscosity rating is usually recommended for use in a differential carrier for a
truck operating in temperatures of -30°F (-34°C)? - correct answer ✔✔75w
Which type of lubricant is recommended when hypoid gearing is used in a differential carrier? -
correct answer ✔✔any EP-rated lubricant
