Oil panThe removable pan on the bottom of the engine. The engine oil drains back into it.
TransmissionThe gearbox, bolted to the back of the engine. The driveshaft comes out of its tail.
DriveshaftThe long shaft from the transmission back to the rear axle. It carries the power.
Universal jointLets the driveshaft keep turning while it runs at an angle. There is one at each end.
DifferentialIt turns the drive through a right angle to the rear wheels. It also lets the two wheels turn at different speeds in a turn.
Rear axleThe housing that runs from the differential out to each rear wheel. An axle shaft inside each side turns the wheel.
Exhaust 5
Exhaust pipeCarries the exhaust gas from the engine back to the catalytic converter. Then on to the muffler.
Catalytic converterIt turns toxic gases in the exhaust into less harmful ones. That happens before they leave the car.
Heat shieldA metal plate between the catalytic converter and the floor. The converter gets hot enough to need one.
MufflerIt cuts the noise of the exhaust.
TailpipeThe exhaust piping from the muffler to the rear of the car. The gas leaves there.
Fuel and brakes 3
Brake linesThin steel pipes that carry brake fluid under pressure. They run from the master cylinder to the brake at each wheel.
Fuel linesThin pipes that carry fuel between the fuel tank and the engine.
Fuel tankStores the fuel. On this car it sits behind the rear axle. Two straps hold it up.
Frame and body 5
CrossmemberA steel beam across the car that joins the two frame rails. This one carries the back of the transmission.
Frame railOne of two long rails that run the length of the car. On a car with a unitized body the rails are part of the body itself.
Floor panThe large sheet-metal stamping that forms the floor of the car.
Rocker panelThe part of the body below the door openings. It runs between the front and rear wheels.
Jacking pointA spot made for the jack. Use the one nearest the wheel you are changing; the owner's manual shows where they are.
How this list was compiled: Read 2026-09-30; a name is kept only where at least two of these use it. (1) US Army, TM 9-8000, Principles of Automotive Vehicles (1985, public domain), https://archive.org/details/tm-9-8000-principles-of-automotive-vehicles-1985 : oil pan (the removable lower part of the crankcase), chapter 7 exhaust system (exhaust pipe between the exhaust manifold and the muffler, the tailpipe leading from the muffler to the rear of the vehicle, the catalytic converter and the heat shield between it and the vehicle floor), fuel tank and fuel lines, paragraph 34-28 brake lines, frame side rails and crossmembers, propeller shaft, universal joints, differential, rear axle housing. (2) Virginia Administrative Code, Motor Vehicle Safety Inspection Regulations: 19VAC30-70-300 Muffler, exhaust system (muffler, catalytic converter, exhaust pipe, tailpipe); 19VAC30-70-320 Fuel system (fuel tank, fuel lines); 19VAC30-70-120 Frame (frame, cross-member, side rails, unitized body, transmission mounts); 19VAC30-70-270 Floor pan; https://law.lis.virginia.gov/admincode/title19/agency30/chapter70/ . (3) Two makers' owner's manuals on archive.org, for naming only: jacking point (https://archive.org/details/manuals-plus-2007-honda-ridgeline-owners-manual-2362b88b), jack point and rocker panels (https://archive.org/details/toyota-camry-1998-owners-manual), oil pan (https://archive.org/details/manualzz-id-1276297). (4) Wikipedia, text only: Exhaust system, Catalytic converter, Muffler, Drive shaft, Fuel tank, Floorpan, Glossary of automotive design (rocker). Licence: own work
The drawing: Drawn for this site on 2026-09-30 from plain geometry; no maker's car, nothing traced. Licence: own work
How it works
A rear-wheel-drive car seen from underneath, as on a lift, with the front at the top. The first view is the front half and the second the rear half. Tap a part to read what it does.
Read the full guide
Front to back
Down the middle run the oil pan under the engine, the transmission, the driveshaft and then the differential in the rear axle. The exhaust runs beside them: exhaust pipe, catalytic converter, muffler, tailpipe. The fuel tank is at the back, and thin fuel and brake lines run along the frame rails.
The body from below
The floor pan is the floor of the car. A rocker panel runs under the doors on each side, and the jacking points are on it, one near each wheel.
A front-wheel-drive car looks different underneath: the engine drives the front wheels only, so no long driveshaft runs to the back.
Questions and answers
What is under a car?
The frame rails and floor pan, the oil pan and transmission, the driveshaft, differential and rear axle on a rear-wheel-drive car, the exhaust system, the fuel tank, and the fuel and brake lines.
What are the exhaust parts of a car?
From front to back: the exhaust manifold on the engine, the exhaust pipe, the catalytic converter with a heat shield over it, the muffler, and the tailpipe to the rear of the car.
Where are the jacking points on a car?
On the underside of the body near each wheel. Put the jack under the one nearest the tire you are changing. The owner's manual has a picture of the exact spots on your car.
Do all cars have a driveshaft underneath?
No. On a front-wheel-drive car the transmission and final drive share one housing beside the engine and drive the front wheels, so there is no long driveshaft and no differential at the back.