Final Drives

Question 1

One advantage to a final drive is
______________

Answer 1

it allows the other power train components to carry less load

Question 2

One function of the sprocket shaft is __________________

Answer 2

to support the track frame

Question 3

The type of reduction which may be inboard or outboard is the _________________

Answer 3

planetary drive

Question 4

The simplest type of shovel drive is
________________

Answer 4

Chain

Question 5

Planetary final drives are ____________

Answer 5

double reduction

Question 6

Single reduction final drives use a ____________ system of lubrication.

Answer 6

splash

Question 7

Mechanic A says that when you are draining the oil from a final drive, if you see any metal particles in the oil you must immediately overhaul the drive

Mechanic B says that all track machines must be jacked up and have the track frame removed in order to service the final drive

Who is right?

Answer 7

Neither is right

Question 8

Before you begin to take a final drive apart you should ___________

Answer 8

wash the entire area thoroughly

Question 9

Misalignment of gears will generally cause _______________

Answer 9

interference wear

Question 10

Mechanic A says that bent axles can be straightened and reused.

Mechanic B says that the oil pump and filter should be serviced thoroughly when the final drive is serviced.

Who is right?

Answer 10

B is right

Question 11

The advantage of a double reduction final drive is that it can provide a greater _________ to the sprocket in the same space as a single reduction gear drive can

Answer 11

torque

Question 12

Lubrication for double reduction final drives can be either a ____________ or __________, depending on the size of machine and the manufacturer.

Answer 12

splash or a pressure feed system

Question 13

A planetary gear system has two advantages. What are they?

Answer 13

1. Performing a high reduction within a limited space
2. Allowing the first reduction gears to carry less load and thus to be lighter (reduced gear width).

Question 14

In a pressurized system, oil is picked up through a screen at the bottom of the housing by a ___________ driven by the _________. The oil flows through a full flow filter and is fed to all the vital areas requiring lubrication.

Answer 14

gear pump
idler gear

Question 15

The three types of final drives used on crawler dozers, excavators and loaders are:

Answer 15

1. single reduction final drives
2. double reduction final drives
3. planetary final drives

Question 16

A single reduction final drive has one set of ___________

Answer 16

gears

Question 17

A single reduction final drive has one set of gears. These gears are: ______________ and ______________

Answer 17

1. the final drive pinion gear
2. the final drive sprocket gear (bull gear)

Question 18

Where are the final drive pinion gear and the final drive sprocket gear (bull gear) usually located?

Answer 18

They are usually contained in one- piece housing which is bolted to the steering clutch housing.

Question 19

The intermediate pinion and gear set are splined together on the same shaft and are usually supported by ___________________

Answer 19

a large tapered roller bearing at each end

Question 20

How is the preload adjustment set in an intermediate pinion and gear set?

Answer 20

Shimming the bearings

Question 21

What is the difference between how double reduction drives are lubricated now, versus how they used to be lubricated?

Answer 21

Newer double reduction drives are pressure lubricated, older units use splash method

Question 22

The final drive is the final stage in a series of reductions that begin at the ______________

Answer 22

engine flywheel

Question 23

The final drive begins at the engine flywheel, flows through the __________ and ______ ends at the final drive (wheels or tracks)

Answer 23

torque converter
transmission

Question 24

_____________ can be defined as a condition that occurs between the surfaces of mating parts that are subjected to high torque loads

Answer 24

surface fatigue

Question 25

Which type of final drive would likely produce a relatively smooth, flat fracture pattern?

Answer 25

shock load

Question 26

What indicates a fatigue type failure in the final drive gear components?

Answer 26

pitted and spalled tooth surface

Question 27

What type of final drive failure can result in a component becoming blackened and discolored?

Answer 27

lubrication

Question 28

In a final drive on a dozer, if a sun gear in the planetary final drive is driven and the ring gear is stationary, how will the planet piston carrier rotate?

Answer 28

In the same direction as the sun gear

Question 29

What is backlash?

Answer 29

The clearance between the crown teeth and the pinion teeth

Question 30

Which type of chain is used in grader final drives?

Answer 30

roller

Question 31

What must be done to determine grader drive chain elongation dimensions?

Answer 31

Hang the chain from a hoist, attach a scale, and place the chain under tension

Question 32

Where does the final gear reduction occur in a single reduction final drive on a bulldozer?

Answer 32

Pinion drive

Question 33

What would indicate that the lube level in a dozer final drive housing was acceptable?

Answer 33

Oil level is exactly even with the bottom of the filler hole

Question 34

When (at what temperature) is the correct time to drain the final drive oil during a regularly scheduled lube change?

Answer 34

At operating temperature

Question 35

What is the main purpose of the final drive?

Answer 35

To increase torque and decrease speed

Question 36

___________ are designed to support the weight of the machine and have to absorb the torque and shock loads at the wheels or tracks

Answer 36

final drives

Question 37

What are the 3 types of drive systems?

Answer 37

1. Planetary Drive 2. Pinion and Bull gear 3. Chain

Question 38

What are two main causes of overheating?

Answer 38

Overload improper lube