Driveline fundamentals and service

Question 1

what is a drive train

Answer 1

the entire arrangement of various major components and connecting drivelines

Question 2

what is the basic function of a driveline

Answer 2

to transmit power from the drive unit to the driven unit

Question 3

when are single drivelines used

Answer 3

if the operating distance between a drive and driven unit is within allowable limits

Question 4

what determines the limit of the driveline length

Answer 4

shaft torque loads - shaft speeds and diameter of the tube

Question 5

when are multiple drivelines used

Answer 5

when using a tandem rear axle

Question 6

what is a midship bearing

Answer 6

a support bearing for a long driveline used to carry the weight of the first shaft and secure its position in relation to the second shaft

Question 7

driveline construction is usually made up of several different components that must be

Answer 7

welded together and balanced

Question 8

what might be the cause of a slightly bent or twisted driveline tube

Answer 8

vibration

Question 9

what is the purpose of U-joints

Answer 9

they allow the transmission of power from one major component to another

Question 10

what should be remembered when installing the u-joints

Answer 10

the grease fitting is installed so it wont interfere with other components and is easily able to be greased

Question 11

what is a trunnion

Answer 11

a highly polished bearing surface at the end of each universal joint cross arm

Question 12

what is in each bearing cap that fits over the trunnion

Answer 12

needle bearings

Question 13

when installed in the yoke the universal joint bearing cap and trunnion bearing cap allows for

Answer 13

a certain amount of pivoting action to occur

Question 14

yokes are

Answer 14

the devices used to make connections to universal joints

Question 15

what type of yoke would allow the shaft assembly to change in length

Answer 15

slip yoke or (sleeve )

Question 16

what will regular lubrication help provide on a slip yoke

Answer 16

control load stress on the splines and enables the splines to smoothly slide together during operation

Question 17

what is another name for a mid-ship bearing

Answer 17

a steady bearing

Question 18

the center support bearing is

Answer 18

a sealed bearing and cannot be lubricated

Question 19

why should you never wash an old center support bearing with solvents

Answer 19

because this would remove the grease from the bearing making it unserviceable

Question 20

what is one way to protect an old center support bearing

Answer 20

packing water resistant grease around the outside of the bearing on both sides

Question 21

what is the maximum working angle difference allowable on a parallel drive shaft design

Answer 21

1 degree

Question 22

what is a broken back driveline

Answer 22

when the major components are to close for a parallel design . so the center line of the drive input and output intersect when extended toward each other over the middle of the driveline

Question 23

what is the purpose of the retaining clips or wire on the bearing caps

Answer 23

to prevent them falling off and losing the needle bearings during removal or installation

Question 24

when inspecting the universal joint what damage would you be looking for

Answer 24

pitting - end galling - brinelling - spalling

Question 25

what may be caused by heavy work loads resulting in a breakdown of the bearing surface

Answer 25

spalling

Question 26

what might be caused by lack of lubrication or incorrect working angle

Answer 26

end galling

Question 27

what would having zero working angle or lack of lubrication cause

Answer 27

false brinelling

Question 28

what would contaminated lubricant cause

Answer 28

pitting

Question 29

how can you make sure the bearing end cap is fully seated after installation

Answer 29

tap with a soft face hammer then gently tighten bearing cup retaining screws - loosen screws and retorque to spec

Question 30

why is it important to phase a driveline

Answer 30

to ensure the two universal joints on each driveline assembly are correctly aligned with each other

Question 31

how can working angle be measured

Answer 31

with a bubble gauge or inclinometer

Question 32

when using a inclinometer it must have

Answer 32

a degree scale that is accurate within 1/4 degree

Question 33

when using a bubble gauge to measure phase make sure to

Answer 33

always face it in the same direction when reading it . turning it could introduce an error into your measurements

Question 34

if the driveline is in phase but still out of balance what might be the problem

Answer 34

the slip joint was installed 180 degrees out of alignment

Question 35

when measuring working angle and the driveline is sloped up this would be considered a

Answer 35

negative degree reading

Question 36

when measuring working angle and the driveline is sloped down this would be considered a

Answer 36

positive degree reading

Question 37

if a driveline shaft is level when measuring working angle it is considered a

Answer 37

zero degree working angle

Question 38

when measuring working angle and both shafts have a positive or negative working angle then in order to find the total working angle of both shafts you must

Answer 38

subtract your readings - ( if one was 5 and the other was 3 then 5 - 3 = 2 degrees working angle )

Question 39

when measuring the working angles and one side has a negative and the other has a positive then in order to find the total working angle you must

Answer 39

add or readings - ( if one was 2 degrees negative and the other was 1 degree positive then 2 + 1 = 3 the total would be 3 degrees

Question 40

when calculating universal joint working angles you must only work with

Answer 40

one driveline at a time

Question 41

what is a single plane working angle

Answer 41

when the universal joints will have a working angle in either the horizontal or vertical plane but not both

Question 42

what is a compound working angle

Answer 42

when the driveline can be viewed from the top or the side and happens when the transmission and differential are not aligned on both the horizontal and vertical plane

Question 43

universal joint angles must be equal to each other but they must also

Answer 43

be correct for the speed they will encounter

Question 44

in order to determine if a vibration is coming from the engine or in the drivetrain you could preform a

Answer 44

stationary test

Question 45

what would low speed vibration most likely be

Answer 45

wheel/tire or wheel bearing because they turn at about 1/4 speed as the driveshaft

Question 46

at higher speeds a higher pitched sound and vibration will be in a driveshaft how is this confirmed

Answer 46

run the unit up through the vibration then let it coast down through the vibration if the noise and vibration are present during the increase and decrease in speed the problem is the driveshaft