These clutches are prone to slippage and do not provide a positive engagement like a standard transmission. This is critical for trucks since they depend on engine back-pressure to descend safely on hilly surfaces. When hauling important cargo while trying to beat a deadline, the worst thing that can happen to you is your rig developing problems.
Problems with your transmission can have some of the most costly ramifications. The good news is that with a little insight and keenness, big rig drivers can recognize warning signs indicating transmission problems early. As the truck driver, he needs to shift the gears frequently to let the engine run at the most efficient speed. The gears help to divide the speed into semis: the more gear, the narrow powerband.
In this way, truck drivers could shift to the right gear depending on different terrains and load weight, avoiding the shortage of power and waste of fuel. For manual transmission trucks, every gear has a specified range and fuel distribution. Most trucks are diesel vehicles, with engine speed range rpm, which is narrower than gasoline cars.
More gears help to make full use of engine torque within the truck speed range, optimizing the engine efficiency as well. Drivers normally shift the fittest gear all the way depending on road and load situation. For example, if the truck is in empty load, high-speed gear works better to save fuel and time.
When the truck is in full load, the truck could get more power in low-speed gear. This is another main reason for the design of many gears. The more gears ensure the power engine is always working in the economic speed range. When starting or speeding up the truck, low-speed gears could reduce the engine speed, move in gear shifts and save fuel at the same time. Multi-gear is also more fuel saving when the truck is running on mountain roads.
In the long slope road, 3 gears waste too much while the engine power is insufficient in 4 gears. Also, the truck is fuel-guzzling and not in smooth running in 5 gears. More gears help to expand the truck speed range as well.
The more gears, the narrower speed range, the more smooth shifting between 2 neighbouring gears. Truck drivers could select the best gear depending on exact speed, load and vehicle weight. It makes the drivers manage the business in the more safe, productive and comfort way. A truck driver with 12 gears is never going to need first gear unless they are heavily loaded and starting uphill, or they need very fine control for manoeuvring.
They then are unlikely to use all remaining 11 gears and certainly not while changing down while slowing to a stop. Starting in a higher gear is much smoother, and it reduces the chance that the wheels will spin as there is a less rotational force torque able to be exerted on the tyres.
Listen to the engine sound to judge shift points, and lightly feel for the gear, don't grind the tranny. Also, depending on load weight, you don't have to split every gear. To shift gears in a semi truck, start by pushing down on the clutch pedal and moving the shifter into the Lo-gear position.
Next, push down on the accelerator, release the clutch, then depress the clutch slightly as you pull the gear shift into neutral. Then, depress the clutch all the way to the floor, and push the gear shift into first as you release the clutch.
Continue this pattern for the first half of the gears, then flip the range selector to 5-H, or fifth gear, to avoid grinding gears when you switch back into the first position.
To learn more, like how to downshift when you need to slow down, keep reading! Did this summary help you? Yes No. Log in Social login does not work in incognito and private browsers. Please log in with your username or email to continue. No account yet? Create an account. Edit this Article. We use cookies to make wikiHow great. By using our site, you agree to our cookie policy. Cookie Settings. Learn why people trust wikiHow. Download Article Explore this Article parts.
Tips and Warnings. Related Articles. Article Summary. Part 1. Understand how the gear shift differs from a normal vehicle's shifter. If you're familiar with a manual transmission, the basic principles of the Eaton-Fuller Transmission shifter—the style used in many commercial trucks today—is similar, but more complex. Basically, it's oriented like a five-speed, but with a total of four different ratios at each position, which you toggle by a combination of switches and positions. This results in a total combination of 18 different speeds.
Your index finger operates the range switch, which allows you to flip between high and low at each gear position with your thumb.
Learn the gear shift pattern. Most gear shifts have a diagram displaying the shifting pattern, which will help to clue you into the organization of the gears. First gear is in the same position as fifth, second in the same as sixth, and so on. Remember, at each position, you also have a total of four different speeds, though only two will be accessible, depending on where you shift from.
In first gear, you've got 1L and 1H, as well as 5L and 5H. Practice the gear pattern of the semi while the truck is stopped. This allows you to become familiar with the gear pattern so you can shift up and down without looking.
This will help you keep your eyes safely on the road while driving. These gears give the truck extra power to get up to speed faster. More gears means more energy for pulling all that weight. You learn how to do this right in truck driving school. There are times when you an unexpected halt in the traffic can cause you to slow your truck down rapidly and stop in the midst of heavy traffic.
It could be an accident or a police checkpoint. Trucks can have speed transmissions with more than one reverse gear option. The engine power and the amount of torque an engine has can also determine the number of gears.
Trucks have massive engines that can produce an enormous amount of acceleration and torque. Their brakes and clutch are stiffer as well. That is why these vehicles are more difficult to drive. For manual transmissions, each gear has a particular range and fuel distribution. The gear ratios differ with the engine type and the number of gears.
A normal sedan is started at the first gear, then allowed to gain a certain amount of speed before engaging the second gear. You are always advised not to drive in one gear for too long and not to drive in the low gears for too long. For a sedan, starting in the second gear puts a lot of pressure on the clutch cable and plate and may also damage the pressure plates.
Thus, to get optimal performance, you need to start a car in the first gear. However, this is not the case for trucks. Trucks have huge engines. These engines produce massive acceleration and torque. Thus, truckers usually avoid starting the truck in the first gear to avoid losing control. If you start a truck in the first gear, it gains higher speeds quickly because the first gear has a higher fuel distribution.
Other gear mechanics also contribute to the truck gaining higher speeds. It is, therefore, harder to control the truck in the first gear, and there is a higher possibility to lose control of the truck and cause it to spin. A spinning truck is a great disaster because it can crash into anything or even topple over.
Truckers are often advised to start the truck in the second gear to reduce the shoot-up effect and to make the take-off slower and more controllable. Thus, one reason for trucks having many gears is to compensate the gear ratios for not having to start from the first gear to gain stability. The driver shifts from the second to the fifth gear as you would for a normal sedan, then splits up the gear into the high range. Then, shifts again from the sixth to the ninth gear.
From the ninth gear, the driver splits up to overdrive for the top gear. There are lots of gears in between since all the main gears have a high and low range with different RPMs.
However, their power band is very narrow, and the difference in revolutions between the gears is often less than RPM.
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