Week #5 - Final Drive (Chapters 23, 24) Flashcards
What is the function of a rear drive axle on a truck?
a. It supports the weight of the truck and its load
b. It redirects the torque from the driveshaft to the drive wheels
c. It provides gear reduction necessary to drive the vehicle
d. all of the above
d. all of the above
What gear sets would determine the output gear ratio in a single-reduction rear axle carrier?
The pinion and crown gear set
What is the usual way of supporting a differential carrier input shaft in front of the pinion?
Opposed tapered roller bearings
What is the correct method for removing rivets from a crown gear assembly?
Use a drill and punch
True or False: A single wheel spinout on a tandem drive tractor can destroy a carrier assembly by shocking the gearing when the spinning wheel finds traction.
True
Spinout failures are unavoidable during winter operation
False
A spinout condition can cause a lubrication failure of a final drive carrier.
True
What measuring tool should be used to check crown gear runout?
A dial indicator
True or False: The rear wheels on a tandem drive axle truck will not turn but the drive shaft does, so you will need to pull both axle shafts.
True
What gear lube viscosity rating is usually recommended for use in a differential carrier for a truck operating in temperatures of -30°F (-34°C)?
An EP-rated lubricant
True or False: The tooth contact pattern can be moved closer to the root by increasing the crown gear backlash.
False
Which of the following would be a factor in defining the reduction ratio in differential carrier gearing?
a. the number of teeth on side gears
b. the number of teeth on differential pinions
c. the number of splines on side gears
d. the number of teeth on crown gear
d. the number of teeth on crown gear
Which of the following best describes the two axles on a standard tandem trailer?
a. dead axles
b. drive axles
c. lift axles
d. steer axles
a. dead axles
What gear sets performs the first reduction in a double-reduction differential carrier?
The pinion and crown gear set
True or False: Crown gear backlash is correctly adjusted by alternately loosening and tightening the bearing adjusting rings.
True
What is the correct method for fitting a crown gear to a flange case half?
Heat in a water tank to 170°F (77°C)
In which of the folloiwng axles would you be likely to find a planetary gearset?
a. lift axles
b. double-reduction differential carrier
c. trailer axles
d. single-reduction differential carrier
b. double-reduction differential carrier
True or False: Pinion spiders walk at any time there is differential action.
True
What pinion and crown gear arrangement positions the pinion gear below the centerline of the crown gear?
c. hyboid (hypoid gearset is commonly used on the forward drive axle of a tandem drive)
What is the most common method of managing an interaxle differential lockout device?
a. spring-engaged, electrically released
b. spring-engaged, pneumatically released
c. pneumatically engaged, spring-released
d. hydraulically engaged, spring-released
c. pneumatically engaged, spring-released
Which of the following whould indicate that the level was correct when checking lube oil level in a differential carrier housing with the fill plug removed.
a. oil level within 1 inch (2.5 cm) of the fill hole
b. oil level within one finger joint of the fill hole
c. oil level exactly even with the bottom of the fill hole
d. oil spilling from the fill hole
c. oil level exactly even with the bottom of the fill hole
After a differential carrier overhaul, what method would best ensure that the wheel bearings receive proper initial lubrication?
Jack the axle up at each side for 1 minute, then level and check the fill hole level.
True or False: A truck is producing some rear axle noise that can be heard only during turns, so the problem is probably excessive backlash between the drive pinion and the crown/ring gear.
False
True or False: Spinout failures are often caused by a defect in the interaxle differential gearing.
False
When planning to drain and replace the lubricant in a differential carrier, which of the following is preferred?
a. flush with solvent
b. flush with kerosene
c. drain when the lubricant is at operating temperature
d. drain after allowing to cool overnight
c. drain when the lubricant is at operating temperature
Which of the following restricts normal differential action except during cornering?
a. double-reduction differential
b. two-speed axles
c. no-spin locking differentials
d. controlled traction differential
c. no-spin locking differentials
Which of the following pavement surfaces would fit the description of a split coefficient surface?
a. wheels on right side in gravel, wheels on driver side on pavement
b. driving the tractor in snow
c. wheels on both sides of tractor on low friction coefficient surface
d. wheels on both sides of tractor on high friction coefficient surface
a. wheels on right side in gravel, wheels on driver side of pavement
In a tandem axle power divider, what component drives the helical gear set?
The input shaft
In which of the following differentials would you find friction plates alternately splined to a driver and tanged to the gear support case?
a. two-speed tandem axles
b. controlled traction differentials
c. no-spin locking differentials
d. all of the above
b. controlled traction differentials
True or False: A tag axle on a highway tractor is located in front of a drive axle or axles.
False
When a truck is traveling in a straight-ahead direction, which of the following should be true?
a. Differential action is required
b. Differential pinions do not turn on the spider shafts
c. Differential pinions walk on the spider shafts
d. Differential side gears do not turn.
b, Differential pinions do not turn on the spider shafts
True or False: A truck is producing some rear axle noise that can be heard only during turns, so the likely cause of the problem is excessive backlash between the side gears and the differential pinions.
True
When a gear tooth separates, leaving a smooth, flat fracture pattern, what is the usual cause?
Single shock load
True or False: Most OEMs recommend extended rear axle oil drain intervals when synthetic lubricants are used.
True
What gear combination accommodates a speed difference between the two drive wheels ona drive axle?
The differential pinions and side gear
True or False: During differential action on a drive axle in a turn, the speed increase on the outboard wheel has to be inversely proportional to the speed decrease on the inboard wheel.
True
True or False: The differential carrier should be flushed with kerosene at every oil change.
False
What pinion and crown gear arrangement positions the pinion gear above the centerline of the crown gear?
Amboid (amboid gearset is commonly used on the rear drive axle of a tandem drive)
A pusher axle is located behind a drive axle.
False
What type of failure is usually indicated when a shaft fails, producing a star-shaped fracture pattern?
Torsional failure
What type of bearing is used as a pilot/spigot for supporting a differential carrier input shaft behind the pinion?
Opposed tapered roller bearings
True or False: The rear wheels on a tandem drive axle truck will not turn but the drive shaft does, so the first step is to pull the forward differential carrier.
False
