190303Ja Flashcards
Unsprung weight refers to?
axles, tires and rims, brakes, differentials (underneath frame)
a rear axle needs to be able to handle what weight?
Hint: Haul trucks, articulated trucks
The weight of the bucket being tipped up, when unloading
What is a Bogie axle?
Oscillating axle to keep ground contact
What causes wheel speed differences?
Different size tires, uneven ground, turning, slippage
How can traction control devices be activated?
Operator controlled, automatically applied
Are carrier housings (pumpkin) generally removable?
Yes, some may not be
Full floating axle shafts are equipped on?
On long haul trucks (3/4T and up). *All weight is supported by bearings that support axle housing and wheel assembly** Outboard final drives
Semi-Floating axles are used on?
Small automotive vehicles, carries some of the weight of the machine. There are some on heavy duty equipment
What is on a straddle mount pinion gear?
A 3rd bearing to help support
Axle housing thickness depends on?
GAWR
Selective spacer does what?
Determine or adjust bearing preload. *On a pinion
Shim pack affect?
Pinion gear depth into bevel gear
Describe an overhung mount pinion
Two tapered bearings are used wit a selective spacer to support pinion. Wearker option compared to straddle type
Is overhung or straddle type pinion mount the strongest?
Straddle type is strongest, prevents deflection away from bevel gear
Bevel gear can also be known as?
Ring or Crown
Why is a bevel and pinion gear preferred on what type equipment?
On equipment that travels forwards and backwards evenly, the pinion being in the center line of the crown gear allows the pinion to handle torque forwards and backwards evenly while give the shaft better ground clearance
Axle side gears are always meshed with?
Pinion gears
What do pinion and side gears must have?
Thrust washers
What is a cross shaft sometimes called?
Spider
What are the two halves of a different case?
Plain case half and flanged case half
True or False: Torque will always be delivered in the same amount to each wheel from the differential
True
True or False: Tire pressure, size and wear do not affect stress and wear on differential gears
False
What causes axle housing failures?
Normal wear and tare during normal conditions, excess wear is caused from shock loading or over loading the equipment.
What does the drive axle assembly must do to direction?
change the path of power by 90 degrees
In an open diff how is torque divided to each axle shaft?
even through the gear ratio, but amount can depend on traction
What does torque work directly against?
Hint: good traction vs bad traction
Resistance in the wheel
If a pinion gear has no etched number in it what does it mean?
It is at zero, does not need to be adjusted with shims
Speed is different in torque through a differential in what way?
Speed cannot be lost
If tire scuffing is occurring during turns, what should be inspected?
The differential
What can a transfer case also be called as?
Transfer Gear
What works with a transfer case to split torque equally between front and rear drive shafts?
Standard or planetary inter-axle differentials
What type of interaxle differential allows for speed differences in drive shafts?
Planetary interaxle differentials
True or false: The planetary interaxle differential has an internal (ring) gear.
FALSE
How many diffs can be locked on a vehicle with three axles with differentials?
All three. (example 6x6 drive)
What common types of differential locks are used?
2
Jaw (dog) type clutch
and
disc/plate style clutch
Applying a dog type clutch at high speeds can cause?
pre mature wear
How is a dog type clutch applied?
Operator via air chamber
If a large amount of steel shows up in an oil sample fro the differential with a dog style clutch what could be the cause?
High speed application of the clutch can damage splines leaving particles and potentially larger chunks of material in the oil.
Which type of differential lock is the most forgiving?
Reference to wear/damage
Plate and disc type
What is a sign that a differential lock is not disengaging when supposed to?
during a turn, one wheel will skid
turning can become more difficult
What is the normal condition of a no-spin differential?
Engaged
In a limited slip differential what causes the clutch packs to be applied?
Difference in speed between the two axles
Can the original differential case be used when changing from a normal differential to a no-spin differential?
Yes
You hear a racheting noise from a differential when the vehicle is turning, what could be the cause?
Normal noise during corning using a no-spin differential lock
