Dash Controls

The dash board, behind the steering wheel displays the control panel of the car. Duplicate fragments of the control panel are found in the interior of your vehicle, such as automatic door locks, extra light switches, etc. Many functions of the car are carried out through the dash board, like turning on the headlights, windshield wipers, horn, turn signals, air conditioning, cassette player, etc. It also contains all of your gauges; gas, temperature, tachometer, etc., which enables the monitoring of the operating conditions of your engine and charging system, fuel level, oil pressure and coolant temperature. It ensures that all the controls are within the drivers reach.

Diesel Fuel Injector

The diesel fuel injector is a pressure valve, but it has specific components that allow it to disperse the diesel fuel in set patterns, depending on the design of the valve. Diesel fuel injectors receive the pressurized impulse from the diesel fuel pump, and allow the fuel to enter the combustion chamber when it is needed. If the diesel fuel injectors get clogged, engine performance suffers.

Diesel Fuel Pump

Diesel fuel pumps inject a specific amount of fuel during a specific time, and control the injectors by the pressure waves of the fuel that they pump. The diesel fuel pump has mechanisms in it, which allows more or less fuel to be pumped. If less fuel is pumped into the cylinders, this slows the engine, and vice versa. It thus also regulates the speed. A series of gears link them to the crankshaft or the camshaft, allowing the fuel pump to be driven directly by the crankshaft of the engine. Some may be belt or chain driven.

Differential

The differential is the thing that works both drive axles at the same time, but lets them rotate at different speeds so that the car can make turns. When a car makes a turn, the outer wheel has to turn faster than the inner wheel, due to the difference in the length of the paths they take. The differential is located between the two wheels, and is attached to each wheel by a half-shaft rotated through a bevel gear. Four-wheel drive cars have a separate differential for each pair of wheels. A grooved, or splined, axle side gear is positioned on the splined end of each axle. The side gears are driven by "spider" gears, which are little gears mounted on a shaft attached to the differential case. As it is supported by the differential case, the side gear can turn inside the case. The differential case can be turned, revolving around the axle gears. The differential pinion (a pinion is a small gear that either drives a larger gear or is driven by one) shaft turns the ring gear, which is fastened to the differential case. The propeller shaft (drive shaft) connects the transmission output shaft to the differential pinion shaft. The turning differential case is mounted on two large bearing holders. These bearings are called carrier bearings. The propeller shaft rotates the ring gear pinion, and the pinion turns the ring gear. The ring gear then turns the differential case and pinion shaft, but the axle side gears will not turn. By passing the differential pinion shaft through two differential pinion gears that mesh with the side gears, the case will turn and the axle side gears will turn with it. During turns, the side gears turn at rates dictated by the radius of the turns, and the spider gears then turn to allow the outer wheel to turn faster than the inner one.

Drive Shaft

The drive shaft, or propeller shaft, connects the transmission output shaft to the differential pinion shaft. Since all roads are not perfectly smooth, and the transmission is fixed, the drive shaft has to be flexible to absorb the shock of bumps in the road. Universal, or "U-joints" allow the drive shaft to flex (and stop it from breaking) when the drive angle changes. There are two types of drive shafts, the Hotchkiss drive and the Torque Tube Drive.

Drive Wheel/Axle

The drive wheel is the end of the axle shaft; it has lugs protruding from it. The lugs are separate pieces that are mounted in the drive wheel. The drive wheel bolts onto the brake drum and the wheel rim of the car itself. It is usually a disc about six or seven inches in diameter. Occasionally the drive wheel and the axle shaft are all one piece.

Dynamic Wheel Balance

"Dynamic" balance is the equal distribution of weight on each side of the vertical centerline of the wheel and tire assembly. Unbalance on either or both sides of a plane of rotation, called dynamic unbalance, causes the wheels to bounce, resulting in flat spots on the tire tread and worn ball joints, tie rod ends, steering gears, and shock absorbers. Dynamic unbalance in the front wheels will cause them to wobble.