Gear Changing Techniques for 18 Speed

8/21/2019 Gear Changing Techniques for 18 Speed

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Version: 1.0Title: Gear Changing

TechniquesCode: AQTF-GCT-1.0

Author: Lavina

GoatcherDate: 26/05/09

Gear changing

Techniques

for13 Speed

and

18 Speed

EATON

RoadrangerGearboxes


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18 Speed Road Ranger GearboxC:\Documents and Settings\user\Local Settings\Temporary Internet Files\Content.Outlook\3SEES133\Gear Changing Techniques for 18 Speed . doc



Author: Lavina


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SHIFT PATTERN DIAGRAM

SHIFT PATTERN DIAGRAM 218 SPEED ROAD-RANGER 3

GEAR CHANGING TECHNIQUES 3CLUTCH USE 3

STEP DOWN-CHANGES 4STEP UP-CHANGES 4SKIP CHANGING 5

SPLIT CHANGING OVERVIEW 6SPLIT CHANGING (UP SPLITS) 7

SPLIT CHANGING (DOWN SPLITS) 7COMPOUND CHANGING 8LOW SPEED GEAR CHANGING (UP HILL) 8PROGRESS GEAR-CHANGING 9ESTABLISHING GEAR SPEEDS 10

DOWN CHANGING USING THE TACHOMETER 10REVERSE GEAR 11LO GEAR 12GEAR SELECTION TIPS 12GEARS AND BRAKING 13


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18 SPEED ROAD-RANGER

GEAR CHANGING TECHNIQUES

The task you have set yourself is not an easy one. Your progress dependslargely on your following of instructions from your trainer. We all have to

learn and we all learn and accumulate new skills at different rates.In order for you to consider yourself a competent heavy vehicle operator you

will need to have not only the desire to learn new skills, but also have acompetent level of hand/foot co-ordination, good observation skills and the

ability to maintain these skills once they have been learnt.To be a competent driver you will need to be able to consistently and

competently change gear using all of the following techniques.

Step changes (step ups and step downs)

Skip changes,

Split changes,

Compound changes and,

Mastering the progressive

change technique.

CLUTCH USE

In order to change gears with a constant mesh gearbox you will need to

adopt an entirely different clutch technique to the one you may be currently

using on a synchromesh gearbox.This involves what is known as double de-clutching or double shuffling.

This entails making two clutch depressions for each gear up-change, one toget it out of gear and the second to get it into gear.

Effective clutch control is vital for smooth gear changing. Firstly, to engage

a gear when you are stationary you must ensure that the clutch is fullydepressed so that the clutch brake can be activated. The clutch brake’s job is

to slow down spinning gears so that you can smoothly engage the gear youwant.


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When changing gear however, it is vital that the clutch is not fullydepressed. Fully depressing the clutch when your vehicle is mobile willvery quickly damage the clutch brake. So when you are changing gear all

you will need to do is to depress the clutch to a point where it will break

torque with the engine.What this equates to is a short depression of about 2-4 inches.

(or 5-10 centimetres) past the normal free travel.

Note: Never use the Clutch Brake when upshifting or downshifting.

Use only for initial gear engagement when the vehicle is standing still.

If you need to make a down change, you will have an additional task whenoperating the clutch. This involves depressing the accelerator in between the

first and second clutch depression. The reason for this is that you need tomatch the vehicle’s gear speed to it’s road speed, thereby synchronizing the

gears for a smooth change. How do we achieve this?

STEP DOWN-CHANGES

At the point when the engine delivers its’ maximum torque, e.g. 1000rpm, it

is time to change down. To do this, initiate the following actions:1. When the engine reaches 1000rpm, simultaneously release

accelerator, depress the clutch and move gear stick to the neutral

position.2. Release clutch and depress accelerator, revving the engine to 1500

rpm.

3.

Re-depress clutch and move gearstick into the next lowest gear.

4.

Release clutch smoothly.

STEP UP-CHANGES

Starting with the vehicle in the appropriate gear (that is the gear which will

get your vehicle-mobile without depressing the accelerator…..as a rule ofthumb this will be 1st gear for uphill, 2nd gear for on the flat and 3rd gear ifgoing downhill) the procedure is as follows:

1. Accelerate engine to approx 1200 – 1700 rpm.


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2.

When you have reached the desired revs, simultaneously release

accelerator, depress clutch and move gearstick to the neutral position.3.

Release clutch and position gearstick over the next gear position.

4. Depress clutch and move gearstick into gear.

5. Release clutch smoothly.

N B The change must be completed by a count of 1,2 or before the

engine revs have dropped below 1000rpm. If the engine revs have

dropped below 1000, and you have not yet selected the gear, you will

have to repeat the process by releasing the clutch, re-accelerating the

engine to 1500 – 1700rpm, re-depressing the, clutch and selecting the

gear required.

Always remember the engine is accelerated with the clutch pedal

RELEASED.

SKIP CHANGING

Skip changing is an important technique for you to learn. It will save you a

lot of work, energy and fuel! At the end of the day if the only gear changingyou do is step changing, then you will be changing gears up to 1200-1400

times a day. That is a lot of expended energy. By integrating skip changinginto your repertoire you can reduce your gear changing by up to 50%. To

skip change successfully you will need to do as follows:1.

Accelerate the engine to 1700 rpm.

2. At 1700 rpm, simultaneously release accelerator, depress clutch andmove gearstick to the neutral position.

3. Release clutch and position gearstick over the gear you are skippingto.

4. When engine revs have dropped to 1000 rpm, depress clutch and

move gearstick into gear. (If the revs drop below 1000rpm, release

clutch, rev engine to 1500, depress clutch and put into gear!) 5.

Release clutch smoothly.


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REMEMBER! Skip changing is always done by moving the gearstick in

the same plane, i .e. from left to right and ri ght to left (Not fore and aft)

You can skip from 1st to 3rd from 3rd to 5th, from 5th 7th (All the odd gears are

in the forward part of the shift pattern)

Or from 2nd to 4th, from 4th to 6th from 6th to 8th (All the even gears are in therearward part of the shift pattern)

It is important that when skip changing you do not attempt to put thegearstick into gear too early. When you make a step change the emphasis is

on making the change quickly (on a count of 1,2). Skip changing is different.

If you make the change too quickly the gears will clash, so one of the easiest

way to ensure a smooth change is to say to yourself “Out wait in” as you are

changing gear, and move the stick into gear as you say “in”. Another way isto count “1,2,3,” this will give you the time frame required for the gears to

mesh without clashing.

Do not over-rev the engine, wait until your revs have dropped to 1500revs before depressing the, clutch and when the revs are at 1200 put it

into gear.

SPLIT CHANGING OVERVIEW

L

Located on the gearstick you will find two buttons. The large black button

found the, front is your Range Change button; the down position is low

range, which allows us to Use 1

st

to 4

th

gear, as well as LO or crawler gear.The up position allows us to use 5th to 8th gear.

The grey button on the right hand side of the gearstick is the splitter button.

This will allow you to split LO gear through to 8 th gear, thereby giving us 18

forward gears. With the splitter in the rearward position you have low

split/direct and in the forward position is high split/overdrive.

Rearward for Direct

SPLITTER CONTROLBUTTON

Forward for Overdrive

Up for High

RANGECHANGE

Down for Low


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SPLIT CHANGING (UP SPLITS)

1.

Accelerate engine to 1700 rpm

2. At 1700 rpm move splitter button forward

3.

Release accelerator and then depress and release clutch in one smoothmotion

When using this method be sure to let clutch out gently and don’t be too

quick going on the accelerator, otherwise the gearbox could neutralize!

SPLIT CHANGING (DOWN SPLITS)

When splitting down use the following method:

1. As your engine reaches peak torque e.g.1200rpm move splitter button

back to low split/direct position.2. At 1200 rpm, release accelerator, depress and release clutch in onesmooth motion.

3. Re-depress accelerator.The final action of depressing the accelerator is most important. The gearbox

needs an accelerating engine to provide the inertia for a positive gearchange!

COMPOUND CHANGING

What exactly is compound changing? A compound change is made whenyou change up a gear and split down at the same time.

The compound change is different in that when you move the splitter back tolow split/direct and at the same time change up to the next highest gear, you

will only need to use a single clutch depression.

When would I make a compound change? Basically anytime a vehicle is

traveling up hill compound changing and split changing allows much moreflexible use of the vehicle’s horsepower and torque.

It will save you work (only one clutch depression as opposed to two for a

normal change) and it will save on fuel as well as wear and tear on both thetruck and driver.

Remember, however, that the single clutch depression only works when

you are going UP through the box, not down!


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LOW SPEED GEAR CHANGING (UP HILL)

When moving off on a steep grade, the change you make from either low

gear to first gear; or first gear to second gear will be made more difficult if

you over-rev the engine in an attempt to give the vehicle some speed, or youmove the gearstick too fast to engage a gear. To avoid missed or clashing

gears try using either of the following techniques:

(Technique #1)

With the vehicle in 2nd gear, bring the clutch up to the friction point, when

you feel this, release the handbrake completely. (Don’t try easing the brakeoff slowly, as soon as you feel the friction point, handbrake OFF)

Accelerate to 1800 rpm (no more!). At 1800 rpm, change gears using a timeframe technique similar to that used when skip changing. That is, you need

to wait until your engine revs drop from 1800 to 1200 rpm before selectingthe next gear. Count it in using “1 and 2” as a guide; Your engine revs will

drop from 1800 to 1200rpm in that time, enabling you to smoothly engagethe next gear.

(Technique #2)

Again, with the vehicle in 2nd gear, clutch up, release the handbrake and

gently accelerate to 1000rpm (no more). At 1000rpm, using a single clutch depression, quickly change to the next

gear.When you get your vehicle into the next gear the subsequent changes will

need to be made using what is known as progressive gear-changing.(Technique #3)

Use a progressive technique to change gears. This is described in detail in

the following heading. Always remember that low gears need low revs to

enable a smooth change. High revs in low range coupled with fast gearchanges don’t work. Therefore LOW GEARS LOW REVS .


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PROGRESSIVE GEAR-CHANGING

By using this technique you will save yourself some work, save fuel, and get

into top gear quicker than you would if you took each gear out to maximum

revs.

It works like this: You have just made a low speed change from 1st to 2nd

gear at 1000 rpm using a single clutch depression, now accelerate to 1200rpm and using a double clutch, now change to 3rd gear.

For each subsequent gear change you will need to increase your engine revs by 100 rpm, so your change to 4th gear will be at 1300 rpm, 5th gear at 1400

rpm, and 6th gear at 1500 rpm and so on until you reach top gear or the speedyou require. By using this technique you will be through the gears faster and

smoother.

ESTABLISHING GEAR SPEEDS

In order to be able to select the gear you will need to negotiate a corner orroundabout, you will first need to establish what gear you will need and at

what speed you can select this gear.Firstly, and most importantly, your cornering speed must be no more than

20/25kph. Any faster that this and you run a very high risk of rollover.

Your next step is to establish what speed your vehicle does in each gear at aconsistent rpm (say 1500rpm).

What you will probably find is this:

1st gear @ 1500rpm = 5kph 5th gear @ 1500rpm = 30kph

2nd gear @ 1500rpm = 10kph 6th gear @ 1500rpm = 45kph

3rd gear @ 1500rpm = 15kph 7th gear @ 1500rpm = 80kph

4th

gear @ 1500rpm = 20kph 8th

gear @ 1500rpm = 90kph


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So looking at the chart we can see that in order to negotiate a corner or

roundabout at a safe turning speed we will need to be in either 4th or 5th gear.Assuming you want 5th gear to turn, and remember that your system of

driving requires that you are in gear before you turn, all you need to do is

brake your vehicle to 30kph, at 30kph, out of gear, clutch up, rev to 1500,clutch in, into 5th gear. For 4th gear, brake to 20kp, for 3rd brake to 15kph.

DOWN CHANGING USING THE TACHOMETER

YOU WILL CONTINUALLY HAVE MAJOR PROBLEMS UNLESS

THIS DEVICE IS USED AT ALL TIMES!

For the best results in your down-changes use the following techniques:

(1) To change down one (1) gear:

Brake or slow to 1000rpm in gear, at 1000rpm, out of gear, clutch up, rev to1300, clutch in, into gear.Single gear down changes can be made between 1000 to 1400rpm; just look

at the tacho, establish what revs you are at, and then add 300 revs.

(2) To change down two (2) gears:

Brake or slow to 800rpm in gear, at 800rpm, out of gear, clutch up, rev to

1400, clutch in, into gear.

Using this technique will enable you to smoothly change gears from 8 th to6th, 7th to 5th, 6th to 4th, or 5th to 3rd.

(3)

To change down three (3) gears: Brake or slow to 600rpm in gear, out of gear, clutch up, rev to 1500rpm,

clutch in, into gear.This is possibly the least used of the three techniques. You will-need it if

changing from 8th to 5th, 7th to 4th, or from 6th to 3rd.

So the thing to remember when changing down is how many gears I am

going down, first and foremost.Then what revs do I need to slow to, and finally how many revs do I need to

engage the gear I am selecting.


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REVERSE GEAR

On all Road Ranger gearboxes you will find a reverse gear. Because of the

way these gearboxes are designed it is possible to have access to high and

low range reverse as well as the possibility that this gear can be split as inthe 13 and 18 speeders.The only reverse gear to be used is in low range, so when you find you need

reverse gear, it will always be a case of stop then drop the range change button.

If you do attempt reversing in high range you will very quickly discover thatthe vehicle will bolt on you, thereby running the risk of an accident.

NEVER attempt to move either the range change button or the splitter

whilst the vehicle is moving!

LO GEAR

The 9, 13 and 18 speed Road Ranger gearboxes have a crawler gear. This is

known as Lo Gear. Again because of their design LO gear can be accessedin either low or high range.

Lo Gear must only ever be used in Low Range!

NEVER SELECT LO GEAR IN HIGH RANGE!

The splitter function on the 18 speed can be used to split LO gear if

necessary, but again only in low range.

GEAR SELECTION TIPS

(1) When moving off on an uphill grade, ALWAYS use 2 ND gear. For

exceptionally steep hills or when fully loaded use 1ST

gear.

(2) The appropriate gear is the gear that will get you moving withouttoughing the accelerator.

(3) When moving off on level ground, you can use 2nd gear.

(4)

When moving off on a down hill grade, you may use 3 rd gear. Ifyou continue going down hill, then skip to 5th, then to 7th.

(5)

Use skip changing when travelling on a down hill slope (3 rd, 5th,

7th) or when on level ground (when empty or partly loaded) use 2nd,

4th, 6th.

(6) Never up-skip when travelling uphill. Skip changing is fordownhill only.


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T h iCode: AQTF-GCT-1.0

Author: Lavina

G t hDate: 26/05/09

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(7)

When approaching a steep decline, always ensure that you have the

vehicle in the appropriate gear before descending. Depending onthe gradient, the gear required would normally be 3rd, 4th,5th or 6th

gear. A rule of thumb is whatever gear you use to go up the hill,

choose 1 or 2 gears lower to go down a similar descent.(8)

When traveling uphill always use the splitter. This will reduce the

gap between the gears and it will make your trucks job easier.Remember if you make its job easier, it will help to make your job

easier.

(9) Some heavy vehicles (Mercedes-Benz, Scania and Isuzu) have a

low torque curve and these engines can lug down to as low as 900rpm in the case of Mercedes V8, and 1000 rpm in the case of

Isuzu. What this means is that when your revs get to that point,

instead of changing down one gear, you go down two gears. Tomake this change you will need to accelerate your engine from 900to 1500 or from 1000 to 1600, an increase of 600 revs.

(10) If you wish to make a single down change, before you make the

change, look at your tachometer. Say you’re at 900 revs in gear, tomake your change simply out of gear, and with the clutch up, rev

the engine to 1200 revs, clutch in, into gear. It will always be anincrease of 300 revs.

GEARS AND BRAKING.

As a final point, always remember when you are braking your vehicle to

stop, always brake in the gear you are in when starting to brake. Don’t

change down;

GEARS ARE FOR GO……..BRAKES ARE FOR WHOA!

Gear Changing Techniques for 18 Speed

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