Exam 24: Heavy-Duty Truck Axle Service and Repair

Which of the following gear lubes suitable for use in a differential carrier is rated to have the longest service life?

Which of the following are indications of fatigue-type failures in gear components?

Which of the following would indicate that the lube level in a differential carrier housing was acceptable?

When replacing a damaged crown and pinion gearset,the damaged pinion cone (PC)variation number was +2,and the new PC variation number is specified as -5.If the original shim pack thickness measured 0.030-inch (0.76 mm),what should the new shim pack thickness be?

Technician A says that Roadranger CD-50 meets the API GL-5 standard.Technician B says that an advantage of using a synthetic gear lube such CD-50 is that it can all but eliminate spinout failures.Who is correct?

Which of the following best describe an ideal ring gear tooth contact pattern for a new crown and pinion gearset?

After measuring pinion bearing preload,the preload value measures less than specified.Which of the following steps is required?

How should used gear lube be disposed of from a service facility?

What is the area of a ring gear tooth that is furthest from the center known as?

Technician A says that the lube levels in drive axles on most heavy trucks can be checked by viewing through a hub inspection window.Technician B says that following a differential carrier oil change,each side of the axle should be in turn,be jacked up and held for one minute to ensure that lube gets to the wheel ends.Who is correct?

A fractured axle shaft with a star-shaped fracture pattern indicates that the cause of the failure is related to:

Which of the following gear lube viscosity ratings would best suit severe winter conditions?

What properties are associated with synthetic gear lubes when compared with mineral based lubricants?

Which of the following gear lube viscosity ratings would indicate an oil that would possess the best flow characteristics at 10 degrees Fahrenheit?

When you attach a cord and fish scale to a pinion bearing,what are you about to measure?

When correcting a pinion to crown gear tooth contact pattern that is too close to the top land and off-center,how should you make an adjustment?

Technician A says that a differential carrier thrust screw should be adjusted to the point that it just contacts the thrust block or crown gear.Technician B says that if a thrust screw was to be backed out all the way,the thrust block would drop into the carrier housing.Who is correct?

Technician A says that it is common practice today in truck repair facilities to replace a failed differential carrier with a rebuilt/exchange unit rather than to overhaul the unit in-house.Technician B says that when rebuilding differential carriers,it is good practice to measure shim pack thickness on disassembly because it usually speed reassembly times.Who is correct?

When correcting a pinion to crown gear tooth contact pattern that is too far from the toe,what adjustment should be made?

Technician A says that API GL-6 lubricant supercedes GL-5 and should be used in all current differential carriers.Technician B says that API GL-5 is extreme pressure (EP)rated for use in hypoid gearsets.Who is correct?