Engines are great at making power, but without a good gearbox to channel that power to the ground, your car isn’t much of a car. That’s exactly what a transmission does – it takes rotational force from the engine’s crankshaft and gears it up or down, allowing you to make the most of the engine’s power band and do things, such as slowly climb steep hills or blast down the freeway. There are several different styles of transmissions out there. Today we’ll take a look at the most basic: manual transmissions.
Manual transmissions, also called standard transmissions or stick shifts, were at one time the only option available for drivers. They feature a clutch pedal and a shift lever, either mounted on the steering column, like in this 1951 Ford or on the floor, like in this 1939 Chevrolet Coupe which the driver moves to select the gear of his or her choice. When automatics became more widely available after World War II, manuals continued as both base-level units and as performance options for drivers who wanted to handle the shifting themselves.
Manual transmissions use a smooth flywheel bolted to the engine’s crankshaft. Just behind that is a clutch disc, made of friction material, which is designed to grab at that flywheel. The clutch disc is also directly connected to the transmission’s input shaft. Behind the clutch is a pressure plate, which is connected, either mechanically or hydraulically, to the clutch pedal.
When the driver pushes on the clutch pedal, the pressure plate lifts off the clutch disc, and that allows the engine’s rotational power to disengage from the transmission. That then allows the driver to shift the transmission from one gear into another.
That same pedal is used to slip the clutch slightly on take-off from dead stop, which can be tricky to get right, especially on a hill. But once you get the hang of it, and you get the muscle memory to get it right every time, manually shifting through the gears can be a lot of fun.
Manuals are better than automatics in a couple of ways. They’re a lot simpler internally, usually offer more gears, and tend to last longer than comparable automatics. They also allow engine braking — using the car’s engine to help slow it down. Plus, you’re always in the right gear, since you’re doing the shifting, and the operation can be as smooth or as harsh as you want it to be.
If you’ve ever driven a muscle car, you know that there’s nothing like rowing your own gears in a Hurst shifter-equipped 4-speed behind a thundering V8. This 1970 Chevelle SS 454 is a great example.
Depending on driving habits, clutch replacement can be a regular job, and it’s not usually a small job.
Thankfully, all the parts you’ll need for replacing, rebuilding, or servicing your manual transmission can be found right here on eBay Motors. Whether it’s a clutch kit for your 2000 Camaro SS
or a complete rebuild kit for the Muncie M20 in your GTO, you’ll find what you need here.
Modern manual transmissions tend to be found mostly in performance cars, and they’ve become much more smooth and well-balanced overall since the days of three-on-the-tree shifting and burly muscle car 4-speeds. Most have six speeds, like this Pontiac Firebird T56 and most feature overdrive gears, which allow the engine to work less at highway speeds, using less fuel and pumping out fewer tailpipe emissions. They’re great swaps for earlier cars, especially muscle cars that came from the factory with 4-speed manuals and no overdrive gears.
Next time, we’ll take a look at automatic transmissions.