Driveline and transmission. Flashcards
What are the three main shafts in a rear-wheel drive gearbox?
Input shaft.
Output shaft.
Secondary shaft.
What shaft accommodates the reverse gear?
Auxiliary shaft.
How are the input and output shafts separated on a rear-wheel drive gearbox?
A taper roller bearing.
Where are the input and output shafts on a rear-wheel drive gearbox, relative to each other?
In line with each other.
How are gears selected?
By moving the synchro hub sleeve.
How are gear ratios determined?
The number of teeth on the engaged gear wheels.
Which gears are the result of a compound gear train on a rear-wheel drive gearbox?
All the gears except the fourth.
What is the fourth gear a result of on a rear-wheel drive gearbox?
Direct drive.
Which shafts rotate when a rear-wheel drive gearbox is in neutral?
The input and secondary shafts rotate.
What happens to the output shaft when a rear-wheel drive gearbox is in neutral?
The output shaft does not rotate, but the gears do.
How is lubrication and cooling done in the gearbox?
It is done by the gear wheels splashing oil.
What is the ratio called between the rotational speeds of the input shaft and the output shaft?
The gear index.
How is a gear index calculated?
Gear index = number of teeth(bottom) / number of teeth(top) or gear index = rotational speed(in) / rotational speed(out).
How do you work out the rotational speed of the output shaft?
Divide the rotational speed of the input shaft by the gear index.
What is the forth gear ratio?
1:1.
What is the difference between reverse gear selection compared to the selection of other gears?
It has:
Strait cut teeth.
It slides into gear.
The gear is not synchronised using a synchro hub.
How many gears does it take to have a gear?
At least two gear wheels.
What are the main gears that make up a gear index?
Driving gear wheel.
Driven gear wheel.
What can transmission affect?
Rotational speed.
Torque.
Directional rotation.
What is the ratio between the rotational speed of the drive gear and the driven gear called?
Gear ratio.
When a gear ratio is referred to by a decimal number, it is called a?
Gear index.
What are the types of gears in a gearbox?
Spur and helical.
Does the stud wheel effect the gear ratio?
No.
Which gear wheel has the highest rotational speed?
The one with fewer teeth.
What does dividing the input rotational speed with the gear index give?
The output rotational speed.
If a gear index is greater than one it is a?
Reduction.
Why is a dual transmission used?
To get greater gear ratios. It can be looked at as two separate transmissions.
How do you get the total gear index?
The individual gear indexes are multiplied.
What happens when changing into a higher gear?
The engine speed drops.
What happens when changing to a higher gear?
The engine speed drops.
What is the effect of excessive free play?
Makes it difficult to disengage the clutch / clutch drag.
What is the effect of insufficient free play?
Clutch slip.
What would cause a whine which disappears when the clutch is depressed?
Worn clutch release bearing.
What makes up the cultch release mechanism?
Cable, pressure plate, release bearing and pedal.
What is the effect of air in the hydraulic clutch system?
It is difficult to engage the clutch / clutch drag.
What is the cause of clutch slip?
Insufficient free play.
What is the cause of clutch drag?
Excessive free play.
What is the cause of clutch judder?
Clutch plate torsional spring is broken, worn engine mounting.
What clutch component drives the gearbox?
Clutch friction plate.
What is the purpose of the interlock?
To stop two gears from engaging at once.
When in fifth gear what rotates faster the output or input shaft?
The output shaft.
How are gears connected to the shafts?
They are not they are free to rotate.
What gears are used on a sliding mesh gearbox?
Spur gears.
What would cause a crashing sound when selecting a gear?
A worn synchromesh.
How do you calculate the overall transmission ratio?
Times the gearbox ratio by the final drive ratio.
What is meant by a hypoid axle?
When the pinion is off set to the centre line of the crown wheel.
What would be a typical final drive ratio?
3:1 to 4:1.
What vehicle would a fully floating axle be used on?
Light commercial vehicle.
What test would be carried out to test a CV joint?
A road test using left and right hand lock.
What part of the transmission would fail an MOT?
CV joint and boot.
A vehicle has a fully floating axle, true or false, a broken axle shaft will not cause the wheel to fall off?
True.
What are three advantages of a diaphragm clutch over a multi-coil spring clutch?
- Lower pedal force required.
- Clamping force does not reduce as the clutch centre plate wears.
- It is lighter and more compact.
Why do clutch friction plates have a spring hub?
For smooth clutch engagement.
To reduce torsional vibrations.
Why would you use helical gears over spur gears?
They are quieter and can carry a greater load.
Why does a baulk ring / synchro cone have a screw type finish?
To disperse oil film and prevent baulking.
What bearing does a differential use?
Tapered roller bearing.
