T
tachometer Device used to measure and display engine speed, expressed in revolutions per minute. Syn. tach.
tack welds Series of small welds, spaced approximately 1 inch apart, which are used to hold together two pieces of metal until the final welding can be performed.
taco'd Axlehousings, frames, or other components that have been severely bent, usually from jumping the truck.
tail gunner The last vehicle/driver on a trail ride. The tail gunner is responsible for making sure everyone completes the trail.
tall gears The opposite of low gears, they are represented in ratios that are numerically lower than "low" gears; e.g., 3.08s are taller than 4.10s.
TBI Throttle-body fuel injection.
threshold braking Applying as much pressure to the brake pedal as possible without going to wheel lockup.
throwout bearing On a clutch assembly, a shaft-mounted bearing that is moved from pressure on the clutch pedal and disengages the clutch disc from the engine.
T-case Transfer case.
tie rod Steering linkage between the pitman or idler arm and a steering arm that moves the steering knuckles.
TIG welding Tungsten Inert Gas welding, also referred to as heliarc welding, usually used for joining aluminum and stainless steel.
timing chain/gears Chain or gears that transmit rotation from the crankshaft to the camshaft.
toe-in, toe-out Inclination of a pair of front wheels slightly inward or outward as viewed from the truck's front.
torque converter Fluid coupling between the engine and the automatic transmission. The engine powers a fan-shaped impeller inside the torque converter, which splashes oil onto a turbine (another fan-shaped device), and the turbine transmits its power to the transmission's gearbox.
torsion bar Suspension spring that looks like a long metal rod. One end is attached to the truck's frame, and the other end is attached to the suspension's A-arm. When the A-arm moves, the torsion bar is twisted and then springs back to its original shape, thus its springing action.
TPI Tuned-port fuel injection.
trail boss The leader of a trail ride.
trailer queen A vehicle that's built primarily for show and is trailered to events.
TTB Twin-Traction Beam, a type of Ford front suspension that utilizes an axle assembly with pivot points, allowing the tires to move independently.
tunnel ram Intake manifold with a large plenum and long, straight runners, used for high-rpm engines.
turned turtle A truck that's rolled upside down.
two-bolt main Engine block with its main crankshaft caps held in place by two bolts.
two-wheeling When tires lift off the ground during a tricky maneuver. Syn. bicycling.
U
U-bolt U-shaped bolt commonly used to attach an axlehousing to a leaf-spring pack.
U-joint Mechanical joint that can transmit rotary motion while swiveling. Used at both ends of a driveshaft to transmit power from the transfer case to the differential.
understeer Cornering condition where a truck's front tires lose grip before the rear tires, causing the front end to slide or push toward the outside of the corner.
unglued 1. Damaged or destroyed; a blown-up engine has become unglued. 2. The codriver's mental state following a rollover.
V
vacuum advance Device that advances or retards ignition timing according to the degree of engine vacuum. At low engine speed, there is plenty of engine vacuum, so the ignition is advanced; at wide-open throttle, there is little vacuum, so the ignition remains at its original timing advance.
vacuum secondaries Secondary carburetor barrels that are pulled open by engine vacuum.
valve lift Circular, stemmed device used to control the airflow in and out of an engine; operated by the camshaft/pushrods/rocker arms.
valvetrain The valve lifters, pushrods, rocker arms, and valve springs.
vaporlock Condition where fuel boils within the fuel line or carburetor, causing bubbles to form that impede the fuel flow or cause excessive fuel to flood the carburetor.
variable-ratio steering Power-steering box that varies the steering ratio. At low speeds, the steering response is quicker for maneuverability; at high speeds, the steering ratio is reduced for stability.
ventilate the block To throw a connecting rod through the side of an engine block due to component failure or excessive revs.
venturi Carburetor barrel or throat with a slightly narrowed or hourglass shape to its interior. The small, narrowed area speeds up airflow and helps pull the fuel past the carburetor jets and into the air stream.
VIN Vehicle identification number, a serial number that identifies a vehicle.
W
wail To perform at peak power or efficiency.
wheel adapter Metal plate with wheel studs that allows a wheel with one bolt pattern to be used on a truck with a dissimilar bolt pattern.
wheelbase Distance from the center of a truck's front wheel to the center of the rear wheel on the same side.
wheel travel The total distance a wheel can move up and down; affected by suspension travel and wheelwell clearance. More wheel travel means a more flexible suspension and more potential traction.
white-knuckle An obstacle that is scary enough to make the driver grip the steering wheel extremely tight.
windage tray An internal engine shield, mounted close to the crankshaft and intended to deflect oil away from the crank as it rotates.
wiring harness Major part of a truck's electrical wiring system; a group of wires bundled together.
WOT Wide Open Throttle.
wrist pin Hollow metal tubular pin that attaches the piston to the connecting rod.
XYZ
zerk fitting Nipplelike fitting on suspension and chassis parts and on U-joints, through which lubricant is pumped under pressure to lubricate the components' internals.