Learning to drive an articulated truck (known as a trailer in Mexico, a tractor in Colombia, and a gandola in Venezuela) requires a lot of training and experience, but if you are curious about how to shift gears, you can get a basic understanding of the steps required to that you put them into practice when you want to drive one of these big men. Learn how the gearbox works, how to shift gears, and some tips for when to shift.
Part 1 of 3: Understand the gearbox
Step 1. Understand the difference between the gearbox of an articulated truck and that of a common car
If you are already familiar with the manual gearbox, you will see that the basic principles of the Eaton-Fuller gearbox (which is used in many commercial trucks) are similar, but more complex. Basically, it's geared like a five-speed box, but with a total of four different speeds in each position, which you change through a combination of switches and positions. This results in a total combination of 18 different speeds.
The shift lever has two switches that control air-actuated speeds. One of these is the converter, which has to be down for speeds from "Lo" to 4. The other is the selector, which is used to switch between the high (H) and low (L) position of each speed.. The index finger operates the converter, making it easy for you to use your thumb to switch between H and L in each gear
Step 2. Learn the gearbox pattern
Most levers have a diagram that explains the shift pattern, which helps you get an indication of the gear order. Low speeds are generally differentiated from high speeds by color. Reverse is marked with an "R".
- Speeds from first to fourth are easy, but to change to fifth you must return to first position and then repeat the pattern. First is in the same position as fifth, second in the same position as sixth, and so on.
- Remember that in each position you have a total of four different speeds, but that only two will be accessible depending on the previous position. In first you have 1L and 1H, as well as 5L and 5H.
Step 3. Practice the articulated truck shift pattern while it is off
This will help you become familiar with the pattern so that you can make changes without looking. So you can keep your eyes on the road safely while driving.
- Squeeze the lever so that your index finger reaches the converter, and your middle finger and thumb can reach the selector.
- If you don't have the experience of using the clutch or driving a car with a manual transmission, doing it with an articulated truck will take you much longer to learn. Operating the gearbox itself is already challenging, therefore you should be very comfortable operating the clutch on a common car before attempting it on a trailer. Practice on a manual car.
Part 2 of 3: Change Speeds
Step 1. Start the truck
Step on the clutch to the ground, just like you would a manual transmission car. This stops the transmission gears, allowing the lever to slide to the desired position. Select "Lo" by engaging the lever in the gear called "Lo," usually to the left and then back.
Make sure the converter is down and the selector is also on "L". Now you can start the truck
Step 2. Step on the gas and slowly release the clutch
As you can imagine, when a vehicle has 18 speeds, being in gear Lo with the selector in L will take you at most to 1.6 km / h (1 mile per hour). When you get to this, release the clutch and you are ready to shift to LoH.
To change to LoH you must raise the selector to "H". You have to depress the clutch slightly, but not fully, then release it to shift to LoH
Step 3. Double clutch to change to 1L
Step on the clutch lightly (not all the way down) when the RPM reaches first gear and lower the selector to “L”, then put the lever in neutral and release the clutch. Step down on the clutch again and push the lever to first while releasing the clutch.
This is called a dual clutch and is necessary because you cannot lower or raise the selector while it is in neutral. In other words, you must go back from “H” to “L” before shifting to neutral, and then step on the clutch again to get into first gear. It is laborious
Step 4. Continue this pattern for the first half of speeds
After shifting to 1L you can go up to 1H, thus continuing to accelerate and progress through the pattern to higher speeds.
Repeat the above steps for 1H, 2L, 2H, 3L, 3H, 4L, and 4H. To do it halfway, raise or lower the selector, release the accelerator, and step on and release the clutch
Step 5. Shift to fifth when you are ready
With the selector at "L" raise the converter to enter 5H, which will prevent the gears from grinding when you return to the first position. This is absolutely important. Crank up the converter, then double clutch back to 1 and it will be in fifth gear.
Step 6. Shift to higher gears
The basic principles are now repeated. Keep switching between "L" and "H" to reach 5H, 6L, 6H, 7L, 7H, 8L and finally 8H.
Part 3 of 3: Knowing When to Shift Gear
Step 1. Use the colored indicators on the tachometer
Most RPM clocks are color-coded with the 1500 RPM mark at the top (12 o'clock); this part is commonly green. This is the ideal place to change gears.
- If it hits 1700 or even 2100 RPM you are past the point where you should shift unless you are going downhill. This part is commonly yellow in color with nothing red on top.
- If you are below 1200 RPM and try to shift, the engine will probably jerk and stall.
Step 2. Get used to the conditions to make the changes
After a while you will become familiar with the general positions you need to make the changes, but in instructional school you learn some basic rules.
- You must be in last gear at 80.5 km / h (50 miles per hour) or more. In general, if you are traveling at the speed of a highway or higher, you should always be in the last speed.
- You must be in fifth or sixth for hairpin turns within the city. To avoid stalling, it is best to shift to higher gears.
- Other speed guidelines may vary from transmission to transmission, on different trucks. You should ask your instructor or other more experienced drivers for advice.
Step 3. Shift down whenever you are slowing down
To downshift you have to slow down using the brake, then shift into the proper gear for that speed range. Normally you have to see that the revolutions reach 1400 to 1600 and then slide the lever to the appropriate position for that speed range.
- Do not use the selector in neutral.
- Professional articulated truck drivers don't use the clutch other than to get into first gear. Listen to the sound of the engine to know when to shift and feel the gearbox, do not force the transmission. Also, depending on the load, you won't need to use the selector for each speed.