Constant velocity (CV) joints are located at both ends of a half shaft and their purpose is to transfer the torque from the transmission to the drive wheels at a constant speed while accomodating the up and down movement of the suspension. The inner CV joint connects the shaft to the transmission and the outer CV joint connects the shaft to the wheel.

The stroke cycle of an engine is governed by the crankshaft which serves to regulate the firing order of the cylinders. All cylinders are not on the same stroke at the same time and correct firing order is important to balance engine operation and minimize vibrations. A common firing order for four-cylinder engines is 1-3-4-2 which indicates that cylinders 1 and 3 fire (power stroke)together and cylinders 4 and 2 fire together.

Most modern cars use an independent suspension system on the front wheels. This setup allows each of the wheels on an axle to move independently in response to road level variations. Independent suspension offers much better handling and stability when compared to a rigid axle suspension at the cost of being structurally weaker and more costly to maintain.

Combustion is the burning of an air-fuel mixture to provide energy. It requires the presence of air, fuel, and a heat source to ignite the air-fuel mixture. In the internal combustion engine that powers automobiles and trucks the combustion happens inside the engine utilzing a fuel like gasoline, diesel fuel, or natural gas.

Because a compressed spring will ex­tend violently, shock absorbers must be used to dampen the spring’s compression and extension cycles. Struts combine the spring and shock into one unit