Workbook, Heavy Duty Truck Systems, 6E
Chapter Twenty-Three – Answer Key
1. Technician A says that an interaxle differential lock should be used to lock out
differential action between the wheels on either side of a drive axle. Technician B says
that an activated interaxle differential locks out differential action between the forward
and rear axles on a tandem drive configuration. Who is correct?
2. Which of the following uses two gear sets to provide greater gear reduction and higher
torque at the differential carrier?
3. Technician A says that kerosene should be used to clean and flush a differential carrier
housing. Technician B says that it is always recommended that the factory fill axle
lubricant be drained and refilled after the first 3,000 linehaul miles (5,000 km). Who is
correct?
4. Technician A says that in a tandem drive axle with an interaxle differential, if three
wheels are held and one is allowed to spin out, the rpm of the spinning wheel would be
four times greater than if all four wheels were turning. Technician B says that wheel
spinout is a major cause of differential carrier failure. Who is correct?
5. Technician A says that spinout failures are due to lubrication throw-off caused by
centrifugal force at high rotational speeds. Technician B says that differential carriers
increase input speeds by at least a 3:1 ratio. Who is correct?
6. Which of the following gear set types requires the use of an extreme pressure (EP)
lubricant?
7. When backing under a trailer upper coupler, which of the following on the tractor would
do the most to prevent a possible spinout?
8. Which type of differential carrier would be most likely to have an oil pump to help
distribute lubricating oil in the assembly?
9. Which type of axle half shaft only functions to transmit driving torque to the wheel and
supports none of the vehicle weight?
10. What is the function of a tractor lift axle on a tandem drive axle?