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Chapter 24
End of Chapter Review Questions Answer Key
1. 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?
2. 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?
3. 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 pattern can be moved closer to the root by increasing the crown gear backlash.
Who is correct?
4. 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?
5. Technician A says that spinout failures are often caused by a defect in the interaxle
differential gearing. Technician B says that spinout failures are unavoidable during
winter operation. Who is correct?
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6. Which gear lube viscosity rating is usually recommended for use in a differential
7. Which type of lubricant is recommended when hypoid gearing is used in a differential
carrier?
8. When planning to drain and replace the lubricant in a differential carrier, which of the
following is preferred?
9. After a differential carrier overhaul, which of the following methods would best
ensure that the wheel bearings receive proper initial lubrication?
10. Which of the following measuring tools should be used to check crown gear runout?
11. Which type of failure is usually indicated when a shaft fails, producing a star-shaped
fracture pattern?
12. When a gear tooth separates, leaving a smooth, flat fracture pattern, what is the usual
cause?
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13. What is the correct method for removing rivets from a crown gear assembly?
14. What is the correct method for fitting a crown gear to a flange case half?
15. The rear wheels on a tandem drive axle truck will not turn but the drive shaft does.
Technician A says that the first step is to pull the forward differential carrier.
Technician B says to pull both axle shafts. Who is correct?