2.3 Shifting Gears

2.3 Shifting Gears

Correct shifting of gears is important. If you can’t get your vehicle into the right gear while driving, you will have less control.

Manual Transmission

Basic Method for Shifting Up. Most heavy vehicles with manual transmission require double clutching to change gear. This is the basic method:
1. Release accelerator, push in clutch and shift to neutral at the same time.
2. Release clutch
3. Let engine and gears slow down to the RPM required for the next gear (this takes practice)
4. Push in clutch and shift to the higher gear at the same time
5. Release clutch and press accelerator at the same time

Shifting gears using double clutching required practice. If you remain too long in neutral, you may have difficulty putting the vehicle into the next gear. If so, don’t try to force it. Return to neutral, release clutch, increase engine speed to match road speed, and try again.

Knowing When to Shift Up. There are two ways of knowing when to shift:

Use engine speed (RPM). Study the driver’s manual for your vehicle and learn the operating RPM range. Watch your tachometer, and shift up when your engine reaches the top of the range. (Some newer vehicles use “progressive” shifting: the RPM at which you shift becomes higher as you move up in the gears. Find out what’s right for the vehicle you will operate.)

Use road speed (mph). Learn what speed each gear is good for. Then, by using the speedometer, you’ll know when to shift up.

With either method, you may learn to use engine sounds to know when to shift.

Basic Procedures for Shifting Down
1. Release accelerator, push in clutch, and shift to neutral at the same time.
2. Release clutch.
3. Press accelerator, increase engine and gear speed to the RPM required in the lower gear.
4. Push in clutch and shift to lower gear at the same time.
5. Release clutch.

Downshifting, like upshifting, requires knowing when to shift. Use either the tachometer or the speedometer and downshift at the right RPM or road speed.

Special conditions where you should downshift are:

Before starting down a hill. Slow down and shift down to a speed that you can control without using the brakes hard. Otherwise the brakes can overheat and lose their braking power. Downshift before starting down the hill. Make sure you are in a low enough gear. Gear selection should be based on the steepness of the grade, weather, road conditions and your load.

Before entering a curve. Slow down to a safe speed, and downshift to the right gear before entering the curve. This lets you use some power through the curve to help the vehicle be more stable while turning. It also lets you speed up as soon as you are out of the curve.

Multi-Speed Rear Axles and Auxilary Transmission

Multi-speed rear axles and auxiliary transmission are used on many vehicles to provide extra gears. You usually control them by a selector knob or switch on the gearshift lever of the main transmission. There are many different shift patterns. Learn the right way to shift gears in the vehicle you will drive.

Automatic Transmissions

Some vehicles have automatic transmissions. You can select a low range to get greater engine braking when going down grades. The lower ranges prevent the transmission from shifting up beyond the selected gear (unless the governor RPM is exceeded). It is very important to use this braking effect when going down grades.

Retarders

Some vehicles have “retarders.” Retarders help slow a vehicle, reducing the need for using your brakes. They reduce brake wear and give you another way to slow down. There are many types of retarders (exhaust, engine, hydraulic, electric). All retarders can be turned on or off by the driver. On some, the retarding power can be adjusted. When turned “on” retarders apply their braking power (to the drive wheels only) whenever you let up on the accelerator pedal all the way.

Caution. When your drive wheels have poor traction, the retarder may cause them to skid. Therefore, you should turn the retarder off whenever the road is wet, icy, or snow covered.

Safety First!
Jayson Z