Drive axle assembly fundamentals

Question 1

what are the four functions of a drive axle assembly

Answer 1

1 - withstand and support the weight of the vehicle and load that has been passed through the suspension 2 - provides the last gear reduction in basic powertrain 3 - must change direction of torque by 90 degrees 4 - must transfer torque between the two wheels wile allowing a difference of speed between the two

Question 2

the weight rating that refers to how much each axle can carry is called the ?

Answer 2

gross axle weight rating GAWR

Question 3

the gross combination weight rating refers to the ?

Answer 3

the total combined gross axle weight rating for a vehicle and its trailers

Question 4

why would a drive axle be added to the rear of a truck rather than a non driving (tag or pusher )

Answer 4

increase traction

Question 5

the percentage of grade at which a drivetrain system can start a moving vehicle is called

Answer 5

startability

Question 6

what components are attached to the drive axle housing

Answer 6

suspension - wheels tires and hubs - carrier housing

Question 7

what is the main function of the carrier housing

Answer 7

hold the internal gear components

Question 8

is the pinion bearing cage always a removable component of the carrier housing

Answer 8

false it can be a removable piece of the carrier housing or a integral component

Question 9

how is the over hung pinion different from the straddle mount pinion design

Answer 9

the overhung pinion has a flat surface at the and of the pinion gear and the straddle mount has a short stub shaft that extends past the end of the pinion gear

Question 10

the input drive pinion is in constant mesh with the

Answer 10

bevel gear

Question 11

what is the main purpose of the thrust screw

Answer 11

prevents the bevel gear from deflecting away from the input pinion during heavy torque loads

Question 12

the bevel gear is bolted directly to the

Answer 12

flanged case half

Question 13

the differential pinions are driven by the

Answer 13

cross shafts

Question 14

what is the most common differential carrier system used today

Answer 14

single speed reduction

Question 15

what is the path of power in a single speed single reduction carrier assembly starting with the input shaft yoke and end with the wheel assemblies

Answer 15

input shaft yoke - input drive pinion - bevel gear - differential case - differential cross shaft - differential pinions - axle Side gears - axle shafts - wheel assemblies

Question 16

what is the components that drives the helical drive gear on a two speed double reduction carrier assembly

Answer 16

shift collar

Question 17

how is low gear achieved in a planetary differential carrier assembly

Answer 17

when the sun gear is locked to the retainer plate

Question 18

the torque available to the wheel with good traction in a wheel spin condition is

Answer 18

the same as the spinning wheel

Question 19

when a vehicle is turning a corner the differential assembly will allow

Answer 19

the outer drive wheel to rotate faster than the inner drive wheel

Question 20

where is the inter-axle differential physically located

Answer 20

in the front drive axle assembly

Question 21

what does the input shaft drive with a set of splines

Answer 21

the differential shaft

Question 22

what are the interaxle differential cross shafts driven by

Answer 22

the input shaft

Question 23

what two components are locked by the inter-axle differential lockout assembly

Answer 23

the input shaft and helical drive gear

Question 24

who is a semi floating axle removed

Answer 24

the vehicle weight must be supported and the wheels must be off the ground

Question 25

what is the input member of the planetary system on a drive axle assembly using a planetary final drive system

Answer 25

the sun gear

Question 26

what are the two main drive axle lubrication methods

Answer 26

splash lubrication and combination splash / pressure lubrication

Question 27

how are drive axles filtered

Answer 27

with spin on filters and magnetic plugs and screens

Question 28

does a differential assembly equipped with a no-spin assembly allow for normal differential action when a vehicle turns a corner ?

Answer 28

yes

Question 29

when the operator activates the driver controlled differential lock, the operator is mechanically locking what two components together

Answer 29

one axle shaft to the differential case

Question 30

as the weight of the vehicle increases what will have to bee added to stay within the weight limitations of the road

Answer 30

the number of axles will have to be increased

Question 31

what do the numbers stamped on the pinion and bevel gear relate to

Answer 31

used to calculate the reduction gear ratio of that particular gear set

Question 32

what is another name for the drive axle housing

Answer 32

banjo housing

Question 33

the construction of the axle housing directly relates to the

Answer 33

weight carrying capability of the axle

Question 34

what is the bowl of a axle housing

Answer 34

the opening with a machined mounting surface in the middle in which the carrier assembly is installed and a flange where the braking components are

Question 35

what are the two removable caps at the rear of the housing used to secure

Answer 35

the differential case bearings and adjusters

Question 36

what are the two basic drive pinions used

Answer 36

overhung mount and straddle mount

Question 37

how is the overhung mount pinion supported

Answer 37

by two tapered roller bearings

Question 38

what is the purpose of the stub shaft bearing on a straddle mount design

Answer 38

to prevent the pinion gear from deflecting away from the bevel gear during periods of heavy torque loads

Question 39

how is the straddle mount pinion design supported

Answer 39

with two tapered roller bearings on the long pinion shaft and a single roller or ball bearing on the stub shaft

Question 40

what type of pinion mount design is more suitable fore heavy torque loads

Answer 40

straddle mount design

Question 41

how is the thrust screw positioned

Answer 41

exactly opposite the pinion gear

Question 42

why is the thrust screw positioned exactly opposite the pinion gear

Answer 42

because this is the area where the maximum deflection and thrust loads will occur

Question 43

what are the two halves of the differential case

Answer 43

flanged and plain

Question 44

how are the two halves of the differential case connected and supported

Answer 44

bolted together and supported by a tapered roller bearing on either end

Question 45

what are some of the drive axle carrier assembly configurations

Answer 45

single speed single reduction single speed double reduction two speed double reduction planetary two speed

Question 46

how is the driver controlled wheel lock operated

Answer 46

air applied and spring released