transmissions class 1

Manual Transmission

A gearbox that allows the driver to manually select gear ratios.

Clutch Assembly

Includes the clutch disc, pressure plate, flywheel, release bearing, and pedal linkage, used to disconnect engine power.

Input Shaft

The shaft connected to the clutch that brings engine power into the gearbox.

Countershaft

Also known as a layshaft; carries gear pairs and is always in mesh with the input shaft.

Output Shaft

The shaft that sends power out to the driveshaft or transaxle.

Gearsets

Composed of spur or helical gears that provide different gear ratios for torque and speed.

Synchronizers

Small cone clutches that match speeds of gears before engagement to allow smooth shifting.

Shift Mechanism

Involves the shift lever, linkage, and fork to engage the chosen gear.

Lower Gear Ratios

Short ratios that provide high torque for acceleration.

Higher Gear Ratios

Long ratios that allow better speed and fuel efficiency.

Rear-Wheel Drive (RWD)

A drivetrain layout where power is delivered from the engine to the rear wheels.

Front-Wheel Drive (FWD)

A drivetrain layout where the engine drives the front wheels directly.

Four-Wheel Drive (4WD)

A drivetrain configuration where power is split between front and rear differentials.

All-Wheel Drive (AWD)

A system that automatically distributes power between front and rear axles.

Transaxle

A device that combines a transmission and differential into one unit.

Drive Shaft

A cylindrical tube that connects the transmission to the rear differential in RWD/4WD vehicles.

Propeller Shaft

A long tube that transmits torque from the transmission to the rear differential.

Half Shafts

Short axles that connect the differential to the wheel hub in FWD vehicles.

U-Joints

Universal joints that allow rotation of the drive shaft with slight angles.

CV Joints

Constant velocity joints that provide smooth rotation at steep angles.

Solid (Live) Axle

An axle design where both wheels are connected by one rigid beam, providing strength but less comfort.

Independent Suspension Axles

Each wheel has its own axle, offering a smoother ride.

Open Differential

A differential that allows wheels to spin at different speeds but can cause power loss to a slipping wheel.

Limited-Slip Differential (LSD)

A differential that uses mechanisms to limit slip and send torque to the wheel with more traction.

Locking Differential

A differential that can be locked to make both wheels spin together, beneficial off-road.

Torque Vectoring Differential

An advanced system that uses sensors to control power split for improved handling.

4WD Low (4L)

A setting on a four-wheel-drive system for extra torque, used for off-road situations.

Full-Time AWD

A system that constantly sends torque to all wheels.

On-Demand AWD

A system that operates as FWD or RWD until slip is detected, then engages the other axle.

Advantages of Manual Transmission

Cheaper, provides more control, and can handle more torque; better fuel economy.

Disadvantages of Manual Transmission

Steeper learning curve, more effort required, and slower in traffic.

Advantages of AWD

Better traction in varied conditions, automatic engagement, and a smoother ride.

Disadvantages of AWD

Heavy, complex, and costlier maintenance compared to simpler systems.

AWD vs 4WD

AWD is automatic and good for on-road traction, while 4WD is manual and suited for off-road.

Center Differential

A component in AWD that distributes torque between front and rear axles.

Drivetrain Components

Includes transmission, driveshafts, differentials, axle shafts, and wheels.

Mnemonics for Drivetrain

Transmission = gear selector; Transaxle = trans + axle.

Differential Purpose

Allows different wheel speeds when turning, compensating for varying travel distances.

Engagement of 4WD

The process by which a driver can engage or disengage the four-wheel-drive system.

Torque Split in AWD

The automatic distribution of torque to improve traction based on driving conditions.

Vehicle Examples with AWD

Subaru Outback and Audi Quattro are examples of full-time AWD vehicles.

Vehicle Examples with 4WD

Jeep Wrangler and Toyota 4Runner are examples of 4WD systems used for off-roading.