Glossary of Automotive Terms

Click on any letter to find automotive-related entries beginning with that letter.

Tachometer
The instrument gauge that shows engine speed, or revolutions per minute. On a vehicle with manual transmission, the driver can use the tachometer to tell when to upshift or downshift. Also called tach.
Tappet
A pivoting actuator that opens and closes cylinder intake and exhaust valves.
Term Loan
A loan repaid in a lump sum, including interest, at the end of the loan period.
Termination Fee
An amount sometimes charged at the end of a lease.
Third Party Insurance
Protection for the damage of property or bodies of others.
Throttle-Body Fuel Injection
A form of electronic fuel injection in which the injectors are centrally located in a throttle-body housing that contains a valve to regulate air flow through the intake manifold. Less efficient and precise than multi-port or sequential fuel injection.
Timing Valve
A valve in a fuel injection pump which times the delivery of fuel.
Title
The government-issued document that proves ownership of a specific vehicle.
Toe-in
A wheel-alignment term that indicates the leading edges of a pair of wheels angle slightly toward each other. Front-drive cars are often aligned with slight toe-in to compensate for the effects of torque steer, or the tendency of the front wheels to pull to the side under hard acceleration.
Toe-out
A wheel-alignment term that indicates the leading edges of a pair of wheels angle slightly away from each other.
Top-Fuel Dragsters
The fastest of drag racing vehicles, these have a characteristicly long body and use top fuel which accounts for the tremendous speeds these vehicles can attain.
Torque
A measure of twisting force, given in foot-pounds (abbreviated as lb.-ft.) or Newton-meters (N-m). In the case of an automobile, it is the twisting or rotational force the engine exerts on the crankshaft. Vehicle specifications often include the maximum torque an engine produces at a specific number of revolutions. An engine that produces 200 lb.-ft. of torque at 3,000 revolutions per minute, or 200 lb.-ft.@ 3,000 rpm, accelerates better at low speeds than an engine that provides 200 lb.-ft.@5,000 rpm.
Torque Converter
In an automatic transmission, a fluid coupling or electronic control that transmits power from the engine to the wheels. It allows the transmission to remain in gear while the vehicle is stopped. The fluid absorbs power and prevents the engine from stalling.
Torque Steer
The tendency of the front wheels on a front-drive vehicle to pull to the side under hard acceleration.
Torsion Bar
A simple, rugged type of suspension spring that twists as it is compressed or stretched.
Torsional Stiffness
A vehicle body's resistance to twisting motions.
Total Loss
Any loss of sufficient size where there is nothing left of value of the property.
Towing & Labor
Pays for towing and labor at the site of an automobile breakdown.
Towing Capacity
The amount of weight a vehicle can tow behind it.
Track
Vehicle width, measured from the center of one tire's contact patch to the center of the opposite tire's contact patch.
Traction
The amount of friction between the tire and the ground.
Traction Control
A system for limiting wheel slip under acceleration, thus maintaining each wheel's contact with the road surface. Traction-control systems generally use the anti-lock braking system to stop wheel spin and reduce power from one or more engine cylinders when an electronic sensor detects wheel spin.
Trade-in Value
The amount a dealership credits you for the used vehicle you provide as partial payment for another vehicle. The amount credited is often about 5 percent below the vehicle's wholesale market value.
Trading Down
Buying a less expensive vehicle than the one currently owned.
Trading Up
Buying a more expensive vehicle than the one currently owned.
Transaxle
A combined transmission and differential on front-drive vehicles.
Transfer Case
On four-wheel drive vehicles, a gearbox that allows power to be delivered to front and rear wheels.
Transmission
The gearbox that delivers power from the engine crankshaft to the drive axle or drive shaft. Most modern cars have a five-speed manual or a four-speed automatic transmission.
Transportation Expense
Pays for car rental expenses if the vehicle is not driveable.
Tread-Wear Index
A tire rating consisting of a number followed by two letters, such as 300AB. The number indicates the useful life of the tire, the first letter (A, B, or C, A for best, C for worst) indicates its traction in wet conditions, and the second letter (A, B, or C, A for best, C for worst) its resistance to heat buildup.
Tri-Link Suspension
A fully independent rear suspension featuring a single fiberglass or composite leaf spring.
Trim Level
The level of options or features added to a model (Ford Mustand GT, Chrysler LeBaron XL).
Truth in Leasing
Also known as the Consumer Leasing Act of 1976, this act was designed to protect consumers against inadequate and misleading lease information.
Tune-up
A regularly scheduled maintenance to check normal operation of the vehicle.
Turbine
An integral piece of the turbocharger, this small fan drives the compressor.
Turbo Lag
The time it takes the turbocharger to kick in after the driver accelerates; the lag results because a turbocharger compressor is spun by exhaust gases in the exhaust manifold.
Turbocharged, Turbocharger
Device that compresses and forces extra air into the intake manifold to produce extra power. Both turbochargers and superchargers are used to produce more power without increasing engine displacement, but neither are particularly fuel efficient and both can require costly maintenance as vehicles age.
Turbocharger
By forcing fuel through the engine, this system allows the car to gather more speed.
Twist-Beam Axle
A semi-independent rear axle often used on front-drive vehicles. The horizontal beam, which connects the two rear wheels, can twist to reduce the effect of one wheel's motion on the other. Less expensive and more compact than fully independent suspension.
Twisting
Trying to induce a policyholder under false pretense to terminate an existing policy to take a new one.
Two-Seater
A vehicle that can only accommodate the driver and one passenger.
Two-Wheel Drive (2WD)
A vehicle drivetrain which distributes power to two wheels.

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