How Manual Transmissions Work
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Undercutting the Mitsubishi by a thousand bucks, the Nissan Versa is the cheapest car in America. Transmission gears are always in mesh and rotating, but gears on one shaft can freely rotate or be locked to the shaft. Typically, there are no electrical components, pumps and cooling mechanisms in a manual transmission, other than an internal switch to activate reversing lighting.
Manual transmissions once thrived in this formerly utilitarian segment, but now that pickups many times are thought of as emblems of a lifestyle, the interest in manuals has cratered. The purpose of the modification is to mechanically reduce time between the changing of while accelerating or decelerating, thus improving the automobiles' performance.
How Manual Transmissions Work - The pricier Titanium trim gets an automatic as standard equipment.
It's no secret that cars with manual transmissions are usually more fun to drive than their automatic-equipped counterparts. If you have even a passing interest in the act of driving, then chances are you also appreciate a fine-shifting manual gearbox. But how does a manual trans actually work? With our primer on or slushboxes, as detractors call them available for your perusal, we thought it would be a good idea to provide a companion overview on manual trannies, too. A brief history lesson shows that manual transmissions preceded automatics by several decades. In fact, up until General Motors offered an automatic in 1938, all cars were of the shift-it-yourself variety. While it's logical for many types of today's vehicles to be equipped with an automatic -- such as a full-size sedan, SUV or pickup -- the fact remains that nothing is more of a thrill to drive than a tautly suspended sport sedan, sport coupe or two-seater equipped with a precise-shifting five- or six-speed gearbox. It's what makes cars such as a Corvette, Mustang, Miata or any BMW sedan or coupe some of the most fun-to-drive cars available today. We know which types of cars have manual trannies. Now let's take a look at how they work. From the most basic four-speed manual in a car from the '60s to the most high-tech six-speed in a car of today, the principles of a manual gearbox are the same. The driver must shift from gear to gear. Normally, a manual transmission bolts to a clutch housing or bell housing that, in turn, bolts to the back of the engine. If the vehicle has front-wheel drive, the transmission still attaches to the engine in a similar fashion but is usually referred to as a transaxle. This is because the transmission, differential and drive axles are one complete unit. In a front-wheel-drive car, the transmission also serves as part of the front axle for the front wheels. In the remaining text, a transmission and transaxle will both be referred to using the term transmission. The function of any transmission is transferring engine power to the driveshaft and rear wheels or axle halfshafts and front wheels in a front-wheel-drive vehicle. Gears inside the transmission change the vehicle's drive-wheel speed and torque in relation to engine speed and torque. Lower numerically higher gear ratios serve as torque multipliers and help the engine to develop enough power to accelerate from a standstill. Initially, power and torque from the engine comes into the front of the transmission and rotates the main drive gear or input shaft , which meshes with the cluster or counter shaft gear -- a series of gears forged into one piece that resembles a cluster of gears. The cluster-gear assembly rotates any time the clutch is engaged to a running engine, whether or not the transmission is in gear or in neutral. There are two basic types of manual transmissions. The sliding-gear type and the constant-mesh design. With the basic -- and now obsolete -- sliding-gear type, nothing is turning inside the transmission case except the main drive gear and cluster gear when the trans is in neutral. In order to mesh the gears and apply engine power to move the vehicle, the driver presses the clutch pedal and moves the shifter handle, which in turn moves the shift linkage and forks to slide a gear along the mainshaft, which is mounted directly above the cluster. Once the gears are meshed, the clutch pedal is released and the engine's power is sent to the drive wheels. There can be several gears on the mainshaft of different diameters and tooth counts, and the transmission shift linkage is designed so the driver has to unmesh one gear before being able to mesh another. With these older transmissions, gear clash is a problem because the gears are all rotating at different speeds. All modern transmissions are of the constant-mesh type, which still uses a similar gear arrangement as the sliding-gear type. However, all the mainshaft gears are in constant mesh with the cluster gears. This is possible because the gears on the mainshaft are not splined to the shaft, but are free to rotate on it. With a constant-mesh gearbox, the main drive gear, cluster gear and all the mainshaft gears are always turning, even when the transmission is in neutral. Alongside each gear on the mainshaft is a dog clutch, with a hub that's positively splined to the shaft and an outer ring that can slide over against each gear. Both the mainshaft gear and the ring of the dog clutch have a row of teeth. Moving the shift linkage moves the dog clutch against the adjacent mainshaft gear, causing the teeth to interlock and solidly lock the gear to the mainshaft. A synchronizer typically consists of an inner-splined hub, an outer sleeve, shifter plates, lock rings or springs and blocking rings. The hub is splined onto the mainshaft between a pair of main drive gears. Held in place by the lock rings, the shifter plates position the sleeve over the hub while also holding the floating blocking rings in proper alignment. A synchro's inner hub and sleeve are made of steel, but the blocking ring -- the part of the synchro that rubs on the gear to change its speed -- is usually made of a softer material, such as brass. The blocking ring has teeth that match the teeth on the dog clutch. Most synchros perform double duty -- they push the synchro in one direction and lock one gear to the mainshaft. Push the synchro the other way and it disengages from the first gear, passes through a neutral position, and engages a gear on the other side. That's the basics on the inner workings of a manual transmission. As for advances, they have been extensive over the years, mainly in the area of additional gears. Back in the '60s, four-speeds were common in American and European performance cars. Most of these transmissions had 1:1 final-drive ratios with no overdrives. Today, overdriven five-speeds are standard on practically all passenger cars available with a manual gearbox. Overdrive is an arrangement of gearing that provides more revolutions of the driven shaft the driveshaft going to the wheels than the driving shaft crankshaft of the engine. For example, a transmission with a fourth-gear ratio of 1:1 and a fifth-gear ratio of 0. Thus, fuel efficiency will improve and engine wear will be notably reduced. Today, six-speed transmissions are becoming more and more common. One of the first cars sold in America with a six-speed was the '89 Corvette. Designed by Chevrolet and Zahnradfabrik Friedrichshafen ZF and built by ZF in Germany, this tough-as-nails six-speed was available in the Corvette up to the conclusion of the '96 model year. Today, the Corvette uses a Tremec T56 six-speed mounted at the back of the car. Many cars are available today with six-speeds, including the Mazda Miata, Porsche Boxster S and 911, Dodge Viper, Mercedes-Benz SLK350, Honda S2000, BMW 3-Series and many others. Some of these gearboxes provide radical 50-percent 0. While the bigger cars mentioned above such as the Viper and Vette often have two overdrive ratios fifth and sixth the smaller cars like the Celica and S2000 usually have one overdriven gear ratio sixth and fifth is 1:1. Clearly a slick-shifting manual transmission is one of the main components in a fun-to-drive car, along with a powerful engine, confidence-inspiring suspension and competent brakes. For more information on a manual transmission's primary partner component, check out our basic primer on clutches and.
These transmissions are called sliding mesh transmissions or sometimesbecause of the difficulty in changing gears and the loud grinding sound that often accompanied. The city mileage is 2 mpg better than in the automatic version. Without it, then other than when the transmission is in neutral, the engine and wheels would at all times be inextricably linked, and any time the vehicle stopped, the engine would manual transmission cars. The supercharger and large displacement V8 are gone, replaced by a tech-heavy flat-plane 526 hp 5. Some vehicles, such as andare nearly universally equipped with automatic transmissions in countries such as thebut the opposite is true in. Contemporary automobile manual transmissions typically use four to six forward gear ratios and one reverse gear, although consumer automobile manual manual transmission cars have been built with as few as two and as many as seven gears. Reverse is typically implemented differently; see the section on. And the latest Lotus, the Evora can build serious grip on these roads while also providing a soft, supple ride. A five-speed manual transmission can be paired to the car's 128-horsepower 1. Two are BUICKS, for crying out loud. These transmissions vary from sequential transmissions in that they still allow nonsequential shifts: the SMG system formerly used by BMW, for example, could shift from 6th gear directly to 4th gear. The countershaft is sometimes called a.
