Drive Axle Assembly Service (On-Road)

Question 1

When selecting particular gear oil, what must be considered?

Answer 1

The selection of gears oils is based on the ambient temperature that is expected in the area were a truck is operating.

Question 2

Housing joint leaks are generally contributed to faulty gaskets.
True
False

Answer 2

False

Question 3

Performing a plug swap usually involves:

a. draining all of the drive axle fluid and changing the plugs out.
b. removing the plug and holding the fluid in the drive axle with your finger while inspecting and cleaning the plug.
c. quickly exchanging the plug with another without draining all of the fluid.
d. swapping the fill plug with the drain plug during maintenance.

Answer 3

c. quickly exchanging the plug with another without draining all of the fluid.

Question 4

The temperature at which the truck should be shut down and the cause of the excessive heat established and repaired is:

a. 160F
b. 220F
c. 250F
d. 275F

Answer 4

c. 250F

Question 5

What check must be done before disassembling the carrier assembly?

a. pinion bearing preload
b. backlash
c. input shaft preload
d. pinion gear runout

Answer 5

b. backlash

Question 6

What components should always be changed in sets?

a. bevel gear and pinon gear
b. right and left axle shafts
c. differential pinion gears and bevel gear
d. cross shaft and axle shafts

Answer 6

a. bevel gear and pinion gear

Question 7

A fractured bevel gear tooth at the toe would be caused by:

a. insufficient lubrication
b. improper lubrication
c. shock impact loading
d. all of the above

Answer 7

c. shock impact loading

Question 8

When checking pinion bearing preload using a cord and a spring scale, record the reading required to start the assembly rolling.
True
False

Answer 8

False, read torque while rolling.

Question 9

A positive etch number means the pinion must be positioned:

a. closer to the bevel gear center line.
b. further from the bevel gear center line.

Answer 9

b. further from the bevel gear center line.

Question 10

On some carrier assemblies, a pinion depth gauge is used to determine the amount of shims required to accurately position the input pinion in the differential carrier housing.
True
False

Answer 10

True

Question 11

When adjusting the backlash between the pinion and the bevel gear, if more backlash is required:

a. adjust the flanged half adjuster counter clockwise an the plain half adjuster clockwise the same amount.
b. adjust the plain half adjuster counter clockwise and the flanged half adjuster clockwise the same amount.

Answer 11

a. adjust the flanged half adjuster counter clockwise and the plain half adjuster clock wise the same amount.

Question 12

On a carrier assembly, if a thrust screw is used, mark the spot with the most _____________ the thrust screw side of the bevel gear.

a. back face runout toward.
b. back face runout away.
c. radial towards.
d. radial away from.

Answer 12

a. back face runout toward.

Question 13

To adjust the inter-axle differential shift collar, apply air pressure to the cylinder to get full travel and then limit the maximum travel with the adjusting bolt.
True
False

Answer 13

True

Question 14

Why must the oil level be rechecked after the drive axle assembly is driven for a short period of time and then shut down for five minutes?

Answer 14

This allows time for the gear oil to circulate throughout the system and then drain down into each oil reservoir.

Question 15

Why should a standpipe be installed in the rear axle housing?

Answer 15

When the drive axle assembly is installed at an angle of over 12 degrees, or if the vehicle is expected to operate on steep grades for extended periods of time, a standpipe should be installed to ensure the pinion bearings receive an adequate amount of lubrication.

Question 16

As a maintenance concern, on which shafts should the end play be checked?

a. axle shafts.
b. input shaft
c. output shaft
d. pinion shaft

Answer 16

b. input shaft

c. output shaft

Question 17

When performing the road test, it was discovered that there was a noise that only occurred while cornering. The probable cause is:

a. low lubrication level.
b. worn differential thrust washers.
c. flat spots on the pinion and bevel gear (ring gear) teeth.
d. loose pinion bearings.

Answer 17

b. worn differential thrust washers.

Question 18

When removing the carrier assembly from the drive axle housing, how would you lock the wheel lock assembly in the engaged position?

Answer 18

To lock the wheel assembly, a special bolt threaded into the air fitting port or applying 80 psi to 120 psi shop air to the shift cylinder should be used to lock the shift collar into place.

Question 19

Why must caution be used when removing the case half bolts?

Answer 19

If the differential is equipped with a no-spin traction enhancing device, the case halves will be spring loaded and longer bolts will have to be used to relieve the spring tension.

Question 20

The probable cause of a bent axle housing is:

a. vehicle overloading
b. vehicle accident
c. shock loading
d. all of the above.

Answer 20

d. all of the above.

Question 21

Pinion bearing preload is established with:

a. shims between the bearing cage and the carrier housing.
b. threaded bearing adjusters.
c. different sized bearings.
d. shims between the pinion bearings.

Answer 21

d. shims between the pinion bearings.

Question 22

The specific distance that the pinion and bevel gear are designed to run from each other is called:

a. running distance.
b. nominal distance.
c. working distance.
d. specified distance.

Answer 22

b. nominal distance.

Question 23

When changing the pinion position, a positive etch number always means that more shims, or a thicker spacer is required.
True
False

Answer 23

False

Question 24

Side bearing preload and backlash adjustment is done with:

a. shims between the bearing cage and the carrrier housing.
b. threaded bearing adjusters.
c. different sized bearings.
d. shims between the pinion bearings.

Answer 24

b. threaded bearing adjusters.

Question 25

If the tooth contact pattern shows excessive heel:

a. move the pinion in and re-adjust ring gear for proper backlash.
b. move the pinion out and re-adjust the ring gear for proper backlash.
c. move the ring gear toward the pinion.
d. move the ring gear away from the pinion.

Answer 25

c. move the ring gear toward the pinion.

Question 26

Correct endplay on the input shaft of the inter-axle differential assembly is established with:
a. shims between the bearing cage and the inter-axle differential housing.
b. threaded bearing adjusters.
c. different sized bearings.
d .shims between the pinion bearings.

Answer 26

a. shims between the bearing cage and the inter-axle differential housing.

Question 27

If the carrier assembly was removed because of a failure and the gear oil was contaminated, what extra service procedure must also be done?

Answer 27

If the differential carrier assembly was removed because of a failure and the gear oil was contaminated, the wheel end assemblies must be removed, hubs cleaned and the bearings inspected.