1. The rim
   The wheel hub and wheel knuckle
2. The tires
   The brake caliper

The wheel bearing provides the smooth movement needed between the wheel hub and knuckle. This circular bearing sits between the wheel hub and knuckle to make the wheels rotate easily and friction-free.

1. The connecting rods
   The pistons
2. The gas pedal
   The muffler

The piston rings snap into small grooves in each piston. They prevent fuel from dripping out of the cylinder and into the oil and hold the compression caused by internal combustion in the cylinder, which gives the engine the power to move the vehicle.

1. Serpentine belt
   Alternator
2. Timing assembly
   Muffler

The camshaft or camshafts sit inside the engine block of in the cylinder head, but their mechanical connection is to the timing assembly, be it a belt, chain or series of gears. This timing assembly spins the camshaft, which opens and closes the exhaust and intake valves in the correct timing.

1. The wheels
   Between the engine and the rear differential
2. The pulleys on each accessory (alternator, air-conditioning compressor, power steering pump, etc.)
   The fuel pump

The serpentine belt transfers the engine's power to the vehicle's various accessory systems, like air conditioning, power steering, the alternator and more. If this belt breaks, one or more of these systems will stop working.

1. Timing system pulleys or sprockets
   The top of the engine
2. The cylinders
   The valve cover

The timing belt or chain connects to a series of pulleys or sprockets that keep the entire engine in the correct timing. They synchronize the crankshaft, water pump and valves with the electronic ignition components.

1. The bottom of the engine block
   On top of the engine
2. On the right side of the engine
   Near the gas tank

The engine oil pan bolts to the bottom of the engine and holds all the oil the engine requires. Its placement is the reason why it is so important to not hit speed bumps too fast, as this can cause the car to "bottom out" and damage the pan.

1. The exhaust system
   The engine
2. The emissions system
   The cylinder head

While its exact position varies by vehicle, the muffler always connects to the exhaust system at some point. The muffler helps keep noise to a minimum.

1. The front of the engine block via a bracket
   The rear of the engine
2. The crankshaft
   The camshaft

The alternator uses a bracket to mount it to the front of the engine. This aligns it with the crankshaft pulley and allows a serpentine belt to transfer the engine's power to it.

1. Only the rotors
   The wheels
2. The wheel hubs
   Rotors, calipers and caliper brackets

The brake pads contact several components in normal operation. They sit within the brake caliper bracket and are held in place by the brake caliper. When the caliper squeezes the pads, they contact the rotors to stop the vehicle.

1. The wheel hub
   The rims
2. The struts
   The brake lines

The brake rotor connects to the wheel hub, typically via a small screw. Over time, the heat caused by braking can create a strong bond between the hub and rotor, forcing you to hit the rotor with a mallet to free it.

1. The wheels
   Wheel bearings
2. Rear differential housing
   Differential ports

The rear differential cover connects to the differential housing to protect the rear differential from dirt. This cover also keeps the differential oil in place and lubricates the moving parts.

1. The engine
   The oil pan
2. The transmission
   The gas tank

The oil drain plug screws into one of the lowest parts of the oil pan. Unscrewing this plug allows you to drain the oil for an oil change.

1. Top of the engine block
   Under the engine
2. Behind the engine
   On the side of the engine

The cylinder head sits on top of the engine block, directly above the pistons. It houses the exhaust and intake valves, and in some engines, the camshafts.

1. Steering rack and outer tie-rod ends
   The front hubs
2. The front struts
   The steering wheel

The inner tie-rod end is the connection point between the steering rack and the outer tie-rod end. These components not only allow flexibility, but also allow you to fine-tune the alignment by twisting them.

1. Gas pedal and transmission
   Transmission and steering wheel
2. Gear shifter and transmission
   Transmission and front wheels

The transmission shift linkage is the mechanical connection between the transmission and gear shifter. It transmits the gear you choose inside the vehicle to the transmission. In some modern cars, manufacturers replaced this mechanical connection with an electric one.

1. The flywheel or flexplate
   The side of the engine
2. The wheels
   The bottom of the engine

The transmission connects to the rear of the engine via the flywheel or flexplate. It transfers the power from the engine to the wheels.

1. The engine
   The fuel pump
2. Accelerator cable or sensor
   The Accelerometer

The accelerator pedal delivers the driver's desired power to the engine via a mechanical or electrical connection. In mechanical setups, the accelerator pedal attaches to an accelerator cable to deliver this input. In newer vehicles, a sensor is used to deliver it.

1. The top of the cylinder head
   The engine block
2. The oil pan
   The starter

The valve cover acts as the shield for the top of the cylinder head. It prevents debris from getting into the moving parts and keeps the oil contained in the cylinder head.

1. Steering hub
   Tilting assembly
2. The turnorometer
   The steering column

The steering column transfers the steering wheel input to the steering rack. This is what turns the wheels in the direction in which you turn the steering wheel.

1. The transmission input shaft and flexplate
   The engine
2. The torque shaft
   The crankshaft

The torque converter connects to the engine flexplate and the transmission input shaft to transfer power from the engine to the transmission. The torque converter goes into a lockup mode at highway cruising speeds.

1. The rear wheels
   The transmission and rear differential
2. The engine and rear differential
   The rear differential and rear wheels

The drive shaft connects the transmission to the rear differential. It connects to both the transmission and rear differential to transfer power. In some sports cars, this shaft transfers power from the engine to a rear-mounted transmission.

1. The exhaust system
   The emission-control system
2. The engine
   The muffler

The catalytic converter connects to the exhaust system, but its exact positioning varies by vehicle. This component converts all the toxins in the exhaust into less harmful fumes.

1. The steering wheel
   The front wheels
2. The gear shifter
   The pistons and connecting rods

The wrist pins connect the pistons to the connecting rods. They allow the piston to tilt forward and backward as the connecting rod pumps up and down inside the cylinder.

1. The brake booster
   The brake pedal
2. The wheels
   The engine

The brake master cylinder bolts to a brake booster, which uses a vacuum to increase the power your brake pedal inputs to stop the vehicle. You can generally find this assembly near the rear driver's side of the engine compartment.

1. The engine block
   The camshaft or pushrods
2. The pistons
   The oil filter

The intake and exhaust valves sit in the cylinder head, but they make a mechanical connection to the camshaft in an overhead-cam engine or the pushrods in an overhead-valve engine. The intake valves allow gas and fuel into the engine, and the exhaust valves allow the fumes from the burned fuel to flow into the exhaust.

1. The crankshaft
   The driveshaft
2. The wheels
   The cylinder head

The center support bearing connects to the rough center point of the driveshaft, supporting it and allowing it to rotate freely. When this bearing goes bad, you'll hear a loud grinding noise while driving.

1. Wheel hub
   Lug nuts
2. Brake rotors
   Axles

While the wheels do contact the rotors and lug nuts, their physical connection to a vehicle is via the wheel hubs. Always torque wheels to their proper specification to avoid damaging the hubs or their bolts.

1. The crankshaft
   The connecting rods
2. The camshafts
   The engine block

The pistons make their mechanical connection with the connecting rods. The connecting rods transfer the energy created by internal combustion from the pistons to the crankshaft.

1. Pistons and crankshaft
   Camshaft and pistons
2. Valves and cylinders
   Muffler and catalytic converter

The connecting rods form the connection between the pistons and the crankshaft. They transfer the energy from internal combustion to the crankshaft, which helps move the vehicle.

1. The shocks
   The steering wheel
2. The inner tie-rod end and wheel knuckle
   The inner tie-rod end and strut

The outer tie-rod end is the outermost steering component before the wheels -- it connects the inner tie-rod end and wheel knuckle. The outer tie-rod end turns the wheels and includes a ball joint for flexibility.

1. The crankshaft
   The camshaft
2. The pistons
   The fuel filter

The main bearings connect to the crankshaft and allow it to rotate free of friction in the cylinder block. Without these bearings, the crankshaft would erode and fail over time.

1. Upper strut tower and steering​ knuckle
   The frame
2. The wheels
   Strut control mounts

The upper portion of the strut connects to the strut tower in the front fender, and the lower portion of the strut connects to the steering knuckle. The strut twists to allow the vehicle's wheels to turn.

1. The starter bracket
   The top of the engine
2. The flywheel or flexplate
   The crankshaft

The starter contacts the teeth on the flexplate or flywheel to spin the engine. This spinning helps start the engine.

1. Flywheel or flexplate
   The cylinders
2. The valves
   The cylinder head

The crankshaft connects to the flywheel or flexplate (varies by vehicle). This is the key connection from the engine to the transmission that drives the vehicle.

1. A bracket and the wheel knuckle
   The wheel knuckle and the strut
2. The wheel well
   The rotor

While the caliper does touch the brake rotor, its actual connection point is a bracket that connects to the wheel knuckle. In some cases, the bracket and knuckle are one piece.