Preface . . . 1 1. Introduction . . . 2 Legend figure 00625B . . . 3 2. General description . . . 4 3. Description of components . . . 6 3.1 Control unit . . . 6
3.2 Position cylinder (shift cylinder) . . . 9
3.3 Valve block . . . 9
3.4 relay valve range group . . . 10
3.5 Electronic unit . . . 12
3.6 Ignition key locking . . . 13
3.7 Start security . . . 13
3.8 Neutral position check . . . 13
3.9 Output speed sensor . . . 13
3.10 Clutch operation . . . 13
3.11 Default drive program . . . 14
3.12 Emergency control system . . . 15
3.13 Starting the engine . . . 16
4. Emergency . . . 17
4.1 Start security system Emergency system . . . 17
4.2 Start security system of the AVS system . . . 17
5. Adjusting neutral switch E500 . . . 18
5.1 Adjusting range group . . . 19
5.2 Adjusting gear switch . . . 20
5.3 Bleeding the clutch . . . 22
5.4 Replacing a shift cylinder . . . 23
5.5 Adjusting shift cylinder (long lever) . . . 25
5.6 Adjusting shift cylinder (short lever) . . . 26
5.7 Adjusting outgoing shaft speed sensor . . . 27
5.8 Adjusting input speed sensor . . . 28
6. Towing . . . 29
Appendix 1 . . . 30
Appendix 2 . . . 39
Appendix 3 . . . 43
Decoding list defect code AVS . . . 43
Appendix 4 . . . 45
The basic principle of the AVS system is the operation of the gearbox using a simple switch knob. Electric wiring can easily be bent around corners and the switch knob is small.
Electricity is an ideal medium for fast transmittance of commands. Because manual gear changing takes quite a bit of strength, the change is made by pneumatic cylinders which are operated through a valve block with electric signals.
As the vehicles are equipped with a compressed air system, pneumatic components can easily be used for switch commands.
The AVS system is quite simple, in principle. Each vehicle which is equipped with the AVS system has a control unit, a gearbox and operational components such as air cylinder, air valves, etc. The system is made more complex by a number of safety measures.
In this booklet, we have described the AVS gear change system on a 8S180 gearbox without retarder mounted in a SB 3000 WS chassis.
Legend fig. 1
1 Accelerator pedal 4 Clutch pedal
22 1st/2nd and 5th/6th shift cylinder 23 3rd/4th and 7th/8th shift cylinder 24 Reverse gear shift cylinder 27 Shift turret
28 Shift valve for gear-change group, 5/2 valve 92 Hydraulic line to clutch release cylinder
115 Central pneumatic connection for emergency control system 170 Cable harness
171 Vehicle circuit connector 1 172 Vehicle circuit connector 2 174 Electronic control unit 175 Preselector control
175a Control lever 175b Rotary switch 176 Display unit
177 Diagnostics connection
179 Electronic signal booster module 180 Load sensor
187 Clutch switch
188 Emergency control knob
189 "Clutch hold-down" solenoid valve 190 "Gear engaged" signal sensor
200 Electronic pulse-generating sensor for input speed 205 Indicator switch for "range-change group engaged" 210 Indicator switch for "gear engaged"
215 Electronic pulse-generating sensor for output speed 220 Indicator switch for "reverse gear engaged"
225 Valve block
230 Indicator switch for "transmission in neutral" 231 Default Drive Program toggle switch
232 Default Drive Program control lamp 233 Instrument panel connector
299 EGAS Electronic unit
300 Parking brake/emergency brake valve 301 3/2 valve, air operated spring loaded return 302 5/2 valve, air operated spring loaded return 303 3/2 valve, air operated spring loaded return 304 clutch booster
The operation of manual gearbox requires the use of a gear lever. The handle and gearbox are usually connected by a shift rod or switch cables.
This system has certain advantages: - it is simple and reliable;
- through the handle, the driver feels what the gearbox is doing (it cracks when the wrong gear is selected and the handle cannot be placed in the correct position if the box does not change into this gear).
The system also has a number of limitations, such as:
- restricted distance between the handle and the gearbox; - restricted weight of system of rods;
- strength required to engage gear in synchronized gearbox;
- required strength can only be produced if the handle is large enough; - large handle takes up a lot of space;
- placement of handle is critical in a system of rods; - to prevent wear, system of rods should be oiled regularly;
- sealing of the handle in the floor requires extra attention in a system of rods.
It is especially in a bus undercarriage in which the distance between the driver and the gearbox is large and when comfort during gear change plays an important role, that a system of rods of cables should not be used.
Figure 1 shows an overview of the most important AVS components.
AVS cancels the handle’s resistance and the gearbox’s mechanic force during gear change. The driver operates the gearbox by means of a small control unit which has three drive modes (the so-called DNR-switch) pos. 175b and a control handle pos. 175a. The control unit consists of a number of switches which convert the driver’s commands into electric signals. All signals are transported to the EST 14 unit. When all signals are present and correct, the EST 14 unit will make sure that the correct actions are carried out after depression of the clutch. The solenoid switch valve operates one of the three air cylinders 22, 23 or 24, which will engage the correct gear. The use of AVS hereby enhances comfort during gear change and limits the space that is required.
First, the DNR-switch 175b enables the driver to choose between the (2nd) forward gear (drive mode D) or the reverse gear (R). Then the clutch should be depressed, after which the system slows down the primary and secondary shaft and the preselected gear is engaged.
When drive mode D has been selected on the rotary switch, the clutch should be depressed to initiate the gear change in the gearbox. The clutch plate should disengages completely, thus disconnecting the drive cable from the motor. To this end, a clutch booster is used, which operates air valve 303 during disengagement of the plate. This air valve at its turn operates electric switch 187, which transmits the signal "disengaged" to the AVS system. The electronic unit 174 will now transmit a switch command after which the switch cylinder involved is aerated and the preselected gear is engaged. Both the preselected gear and the engaged gear are at all times visible on the display 176.
A disadvantage of the use of the control handle is that the driver does not feel what is happening in the gearbox. Therefore, a sensor 190 is built into the clutch system. Through pulses in the clutch pedal, the driver feels if the clutch has indeed been engaged and knows if he can release the clutch pedal. If the driver releases the clutch pedal before the gear has been engaged and before the
When the clutch pedal is released, the air in the system drops and gear change is no longer possible.
The electropneumatic nature of the system enables the use of a number of shift securities. Without securities of any kind, the whole system would go down if, for example, the power supply fuse were defective.
Therefore, a number of securities and functions have been incorporated into the system and in addition to the default drive program, a complete pneumatic emergency control system helps cope with all possible situations. This is why the control system is rather complicated.
The system can be roughly divided into 3 parts:
A The main switch system. This is the actual control system in which gears are preselected and engaged depressing the clutch pedal - without use of the control lever.
B The default drive program enables gear change when one of these switches is defective: 1. gear engaged
2. transmission in neutral 3. range group engaged.
In this case, all gears are engaged through the main switch system by operating the control handle rather than automatic preselection.
C The emergency control system in case the main switch system goes down.
In the following description, the working of all components that were used will be dealt with in detail and all sub-situations which may occur while driving are discussed successively.
3.1 Control unit:
The control unit fig. 2 consists of a spring-loaded control lever, which can be pushed forward (+) for shifting up, backwards (-) for shifting down or sideways to the left (N) for putting the transmission in neutral, and of a rotary switch with the following modes: D for forward gears, N for transmission in neutral and R for reverse gear.
The control unit is fully electrical and is attached to the cable harness with a 12-pole connector. This paragraph describes the operation of the switches and the control unit’s output signals.
When turning the rotary switch (or DNR switch) fig. 2, the voltages shown in table I are generated. The switches that are operated are also indicated.
Table I Overview rotary switch * = 24 volt
OUTPUT SIGNAL PRESELECTOR SWITCH
AD1 AD2 AD3
CONNECTOR PIN 3 4 2 WIRE 4833 4832 4690 POSITION PRESELECTOR SWITCH OPERATED SWITCH D S1 * N S1 * R S1 *
- Neutral, pin 2 carries 24 V if the emergency control switch 188 is in position "aus" or neutral switch E500 is closed (input voltage pin 1 and the DNR switch is put in neutral).
Upon operation of control lever 2B, the voltages indicated in table 2 are generated.
Table II Overview control lever
OUTPUT SIGNAL
PRESELECTOR SWITCH
OPERATED SWITCH
AD4 AD5 AD7 S5 S6 S7
CONNECTOR PIN 6 7 9 WIRE 4830 4829 4828 CENTRAL POSITION * SHIFT UP (+) * * X SHIFT DOWN (-) * * X NEUTRAL (N) X
NOTE: - All output signals and operated switches for the control unit can be found in table I and II.
- The control unit receives 24 V through pin 10, wire 4827 if the emergency control switch 188 is put in position "aus".
3.2 Position cylinder (shift cylinder):
The forward gears in the gearbox are engaged with two 3-position cylinders. Fig. 3 shows a cross section of the three different positions.
A. The pulled-out position can be
achieved by aerating the middle M and the right R connection (MR).
B. The central (neutral) position can be achieved by aerating only the middle M connection. The left and right piston are pressed outward, pulling the centre in central position.
C. The pulled-in position can be achieved by aerating the middle M and the left L connection (ML).
In the following diagrams, these shift cylinders are shown schematically. The operation of the cylinders is not shown.
3.3 Valve block (fig. 4.1)
Engagement of the different gears requires eight electropneumatic valves, which are placed together in an aluminium housing. The air connections on the valve block are identical to the connections in the diagrams.
3.4 Relay valve, range group (fig. 5)
A separate relay valve is used for
engagement of the range group. The valve is kept in high range by a built-in compression spring and is put in low-range by air
pressure. The low-range command is transmitted from the valve block.
3.5 AVS Diagram (fig.6)
Figure 6 shows a complete ABS diagram with all components
3.5 Electronic unit EST 14 (fig. 7)
The electronic unit EST 14 controls the operation of the AVS shift system (fig. 1 pos. 174).
On the basis of input information from: - preselection switch
- sensor drive
- sensor output shaft
- switch "range group engaged" - switch "gear engaged"
- switch "transmission in neutral" - clutch switch
- load sensor load signal (digital EMS)
(analogue) eg. Egas
- compression (option) retarder switch
the unit calculates the vehicle’s speed, motor load and acceleration or deceleration.
On the basis of this information, the system determines the right gear for each situation. If the determined gear does not coincide with the engaged gear, the display will show a gear change advice. At the same time, the system is prepared for gear change, so that operation of the clutch switch results in the correct gear’s engagement.
The following functions are also incorporated in the EST 14:
- information supply to the display - system protection against too fast or
incorrect gear change
- error registration plus readout possibility - default drive program
4.
SYSTEM DESCRIPTION
4.1 Ignition key locking
If the vehicle is parked with one of the gears still engaged, the following could happen. Because of air leakage, the air pressure might become too low to operate the clutch pedal, which results in the absence of the release AVS signal. Without air, the gearbox cannot be put in neutral, unless the shift lever on the box is pushed in neutral position by hand via the repair hatch. Normally, the vehicle cannot be started.
Therefore, a separate ignition lock has been fitted, in which the ignition key can only be turned from position 2 to position 0 if the gearbox is in neutral position. When the transmission is in neutral, the ignition key locking (fig. 6) C539 is raised and the key can be turned to the 0 position. The engine will automatically stop if the key is turned to positions 1 and 0. The voltages on engine stop valve B078 is disconnected, pulling the fuel pump in stop position.
4.2 Start security
The ignition key locking also prevents the driver from starting the engine if not all starting conditions have been met.
If the transmission is not in neutral or if the DNR-switch is not in neutral position, relay contact G039 is de-energized and the vehicle cannot be started.
4.3 Neutral position check
The connection between control unit and gearbox is fully electrical. This means that it is not always clear if the gearbox is in fact in neutral position. Therefore, the gearbox has been fitted with a neutral switch (fig. 1 pos. 23 or fig. 6 E500), which transmits the neutral signal to the EST 14 unit, which on its turn shows the neutral signal N on the display when the gearbox is in neutral (vehicle speed under 10 km/h) and the ignition key is in position 2.
4.4 Output speed sensor
The signal of output speed sensor fig. 1 pos. 215 is used for registration of vehicle speed.
4.5 Clutch operation
If you try to put a manual gearbox in reverse gear but the clutch does not engage fully, you can hear a "grinding noise".
This "grinding" is produced because the non-rotating sleeve is pushed against the reverse gear wheel.
Compared with the forward gears, the reverse gear is not synchronized.
The AVS system is activated by means of the clutch switch. The clutch signal is present when the clutch booster supplies air to the clutch switch (E531) via a valve (V6). This valve is integrated in the clutch booster.
The clutch switch transmits the signal to the EST 14.
The clutch booster’s stroke disengages the clutch, whereafter the clutch switch can be operated. If the above-described is to function correctly, there should be no air in the clutch system.
Note:
If the hydraulic part of the clutch operation is not well-vented, the clutch plate will not disengage sufficiently and gear change will not pass correctly. A grinding noise is produced during gear change.
Warning!
4.6 Default drive program
The AVS system needs information from a number of sensors and switches. If one of these switches is defective, or if the switch’s signal does not reach the AVS control unit, the AVS system will no longer operate.
The AVS system can then be switched to the default drive program. In this program, the switches’ signals are not required.
The sensors on the gearbox which send information to the control unit are: - neutral switch
- gear engaged switch - range group switch - sensor input speed - sensor output speed.
The default drive program should only be used if:
1. the gearbox is not mechanically damaged;
2. there is sufficient air pressure for the system (min. 6.5 bar);
3. the display shows one of the error codes mentioned in the table below:
ERROR NUMBER (DECIMAL)
COMPONENT
61 neutral switch interrupted
62 gear engaged switch interrupted
63 gear engaged switch closed
64 range group switch closed
65 range group switch interrupted
67 neutral switch closed
The default drive program is activated by a special toggle switch fig. 1 pos. 6, fig. 6 C665. All gears can now be engaged manually through the control lever, like in a manual gearbox. Push the gear lever forward (+) if you want to shift up and push the lever backwards (-) if you want to shift down. The engaged or preselected gear is shown on the display (fig. 1 pos. 176, fig. 6 B530), together with the spanner symbol. Also, the control light on the SWS panel (fig. 6 pos. D582) is on, indicating the activation of the default drive program.
- Once the default drive program is activated, resetting toggle switch C665 does not deactivate to the normal drive program until the power supply to the EST-14 has been down.
- If the neutral switch does not close, starting and stopping the engine is not possible since wire 4690 is not powered. Use the emergency switch as described below to power wire 4690 directly and reset it to "AVS" after the engine is started.
Fig. 8
4.7 Emergency control system (fig. 8)
Fig. 8 shows a schematic overview of the emergency control system. Each electric system, however well-made, has fragile wiring and connections. It is possible that because of one defective connection, none of the gears can be engaged. Therefore, a separate emergency system has been added. This emergency system works solely on air.
The emergency control system enables pneumatic gear change in the gearbox by means of the emergency system’s control knob (fig.1 pos. 28, fig. 8 C664). With this knob, the neutral position N, first (1) and second (2) gear and the reverse (R) can be engaged without intervention of electric components. The shift cylinder corres-ponding to the control knob’s position is aerated. When the forward or reverse gear is engaged, the relay valve high low (fig.1 pos. 34, fig. 8 V4) is activated in low range. The gears below correspond to the positions on the control knob:
position on knob engaged gear
1 2
2 4
R R
Under no circumstance should the AVS system be able to work if the emergency system is activated. Therefore, a switch 1-3 is opened when switch C664 is operated. This cuts the AVS system’s voltage. When the emergency switch is put in neutral position, contact 2-5 is closed, thus making it possible to start the engine.
The emergency system is also protected against incorrect gear change. This is done in the following way:
- The first gear or reverse gear can only be engaged if the vehicle has come to an absolute stand-still. To this end, the emergency system is accessed via switch valve V2, which is operated through switch valve V2 by park brake valve V5.
- Gears can only be engaged if the clutch plate is disengaged (clutch pedal is pressed down). The required air comes from switch valve V6, which is operated by the clutch booster.
This method’s plus is that when the emergency system is activated, the driver can change gears without having to apply the park brake all the time. Switch valve V1 is in emergency switch position and remains in this position until the AVS system can be activated again, pressing valve V1 in its original position.
Fig. 9
4.8 Starting the engine (fig. 9)
- Park brake applied
- Control knob emergency system in "Aus" position
- Default drive program switch off - Main switch G053 on
- Ignition key in lock, position 2, "ignition on" - Rotary switch control unit in position N,
("N" indicated on display)
- Gearbox in neutral (E500 closed) - Ignition key blockage raised.
Starter motor B010 receives voltage via ignition lock C539 pos. 3, switch start forward/reverse C580, start locking relay G100, neutral position start relay G035 and start relay G038.
The common starting and stopping procedures turn out to cause a number of unwanted situations if combined with an AVS system. To prevent these situations, a special electric circuit has been devised so that:
- the engine cannot be started if the gearbox is shifted into gear.
- the key cannot be taken from the ignition if the gearbox is shifted into gear. - the engine cannot be cut of/by turning the ignition key backwards.
- the main switch cannot be switched off while the engine is running.
5.1 Start security system Emergency system:
If main switch G053 has not been activated, the ignition key can be inserted into the ignition lock and it can be turned as well. The key snaps into position 2 because the blocking relay is not
energized. As long as the main switch has not been activated, the engine cannot be started; the key cannot be taken from the ignition anymore.
As soon as main switch G053 is activated and the ignition key is in position 2,
- ignition relay G015 is energized so that all power consuming elements are connected to the power source (connection point 15);
- fuel valve B078 is actuated via fuse E109 so that the fuel pump is no longer pulled into the stopping position and the engine can be used;
- the neutral switch in C664 is connected to the power source via fuse E054 of the emergency system, energizing relay G039 in neutral position;
- G074 is energized, releasing ignition key locking.
Starting of the engine is achieved by turning the ignition key to position 3. The starting signal then goes from contact 3, via switch C580, start locking relay G100, neutral position starting relay G039 and starting relay G038 to the relay on starter motor B010. The starter motor is engaged.
As soon as the engine engages, the dynamo will supply power, causing relay G100 to de-energize. The starting signal is interrupted and the starter motor is disengaged.
5.2 Start security system of the A.V.S. system:
If the control knob of emergency system C664 is in the "Aus" position, the switch is closed and the contacts 1, 3 and 4 are connected. This supplies power to:
- switch E531, which is operated by the clutch booster - contact 20 of the electronic unit
- contact 10 of control unit C668
- control switch C665 of the default drive program
Because the rotary switch is in position "N", according to table 1, switch S1 in control unit C688 is closed, which causes power to go to contact 2, relay G074 to be energized and the ignition key locking to be lifted.
6. ADJUSTING
6.1 Adjusting neutral switch E500
Neutral switch E500 is a break-switch. Fig. 1 pos. 23, fig. 10 shows the switch as mounted on the gearbox. If this switch has to be replaced, the replacement has to be adjusted by mounting it with a distance washer of the correct thickness. Use a feeler gauge and continuity testing lamp to determine the correct thickness of the washer.
- Remove distance washer from under the neutral switch.
Warning! The ball (3) may fall out if the switch is dismounted.
- Shift switch rod into neutral.
- Screw in the switch until the signal just disappears (test the switch with a
continuity testing lamp). If a testing lamp is used, the light will go out.
- Measure distance B with two feeler gauges (in connection with possible toppling of the switch).
- Find the correct thickness of the distance washer in the table below.
- Clean the surfaces of grease.
- Mount the switch and the distance washer with tightening torque 50 Nm
Fig. 10
1. Neutral switch
2. "Gear engaged" switch 3. Ball
Table for the aluminium distance washer, mounted without lubrication.
Distance B 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7
Distance washer
1.8 1.8 2.0 2.0 2.2 2.2 2.4 2.4 2.6 2.6 2.8 2.8 3.0 3.0
Check correct operation of the switch: - gearbox in neutral: light on;
- gearbox in gear: light off.
6.1 Adjusting range group switch
The switch for the range group is a break-switch and is identical to the neutral break-switch.
Fig. 11 shows the position of the switch as mounted on the gearbox. When replaced, the switch does not have to be adjusted, but has to be mounted with the supplied
distance washer.
Follow the steps below if adjustment is required:
- Remove the distance washer from under the neutral switch.
- Put the switch shaft into middle position with the aid of compressed air.
- Remove connection p25 and p26 on the cylinder of the range group.
- Briefly aerate p25 or p26 until the gap in the control pin is visible for the entire diameter of the switch shaft. The switch shaft is now in the middle position. - Screw in switch until signal is lost. - Measure distance D with two feeler
gauges (in connection with possible toppling of the switch).
- Suppose D = 2.6 mm
distance washer Z thickness = D - (0.8+0
+0.2
) mm
maximum thickness distance washer = 2.6 - 0.8 = 1.8 mm.
minimum thickness distance washer = 2.6 - 1.0 = 1.6 mm.
Choose the correct distance washer. The aluminium washers can be supplied in the following thicknesses:
- Clean the surfaces of grease and install the switch and washer.
Tightening torque switch = 50 Nm
Tightening torque threaded bush = 50 Nm
6.3 Adjusting gear switch
The gear switch is a make-switch. Fig. 12A and 12B shows the switch as mounted on the gearbox. When replacing the gear switch, it has to be adjusted by mounting it with the correct distance washer thickness. A continuity testing lamp and feeler gauges are used to determine the correct thickness of the distance washer.
Fig. 12A
Determination of the thickness of the distance washer.
1 Shift into 1st gear with default drive program.
2 Screw in switch until testing light goes on (switch closed).
3 Activate all gears one by one. Check if the testing lamp goes on for all gears. 4 Repeat step 2 and 3 if the testing lamp does not burn for one of the gears. 5 Shift gearbox into neutral.
6 Start engine. Shift into reverse and slowly release clutch to verify that reverse gear is selected and turn engine off. Repeat step 2 if the testing lamp does not burn.
7 Measure distance X with two feeler gauges (in connection with possible toppling of the switch). 8 Find the correct thickness of the distance washer in the table below.
Table for the aluminium distance washer, mounted without lubrication.
Distance X 3.3 3.2 3.1 3.0 2.9 2.8 2.7 2.6 2.5 2.4 2.3 2.2 2.1 2.0 1.9 1.8 Distance washer 2.6 2.4 2.4 2.2 2.2 2.0 2.0 1.8 1.8 1.6 1.6 1.4 1.4 1.2 1.2 1.0
Verification of the adjustment.
9 Shift into neutral.
Screw in switch to distance Y. Signal should not come in.
- Horizontally mounted neutral switch. Distance Y = X - 1 mm
- Neutral switch mounted in 45°angle. Distance Y = X - 1.2 mm Example: Horizontal version. Distance X = 2.6 mm Distance Y = 2.6 - 1.0 = 1.6 mm Further check.
10 The difference between X and Y must be equal to or larger than 0.3 mm (X - Y≥0.3)
Clean the surfaces of grease and install the switch and correct distance washer with a 50 Nm tightening torque. If the difference between X and Y complies with this.
6.4 Bleeding the clutch
Follow the steps below to bleed the clutch system (see fig. 13A):
1 Pressurize the compressed air system until maximum system pressure.
2 Fill the clutch fluid reservoir completely. 3 Connect vent lines to the bleed nipples of
- the "gear engaged" sensor - the "clutch hold-down" valve - the clutch booster
Note: The component that is placed highest, should be vented first. In this case, this component is the "gear engaged" sensor. 4 Open the bleed nipple of the sensor and
step on the clutch pedal until no more air bubbles are visible in the out flowing clutch fluid.
Warning: Make sure the clutch fluid level remains above the minimum level.
5 Close the bleeding nipple while the clutch pedal is down.
6 Remove the vent line and place the protector cap on the bleeding nipple. 7 Repeat steps 4-6 for the other two nipples. 8 Fill the clutch fluid reservoir until the
maximum level.
Warning: If the clutch pedal is released too soon, the following situation may arise (fig. 13C)
The clutch booster remains aerated because the "clutch hold-down" valve is activated. The clutch pedal is not operated.
In these circumstances, the clutch pedal’s locking pin may drop out of the main cylinder’s piston, preventing the clutch from engaging fully.
Fig. 13A
Fig. 13B
Replacing a shift cylinder:
Two identical shift cylinders are mounted on top of the gearbox (fig. 1 pos. 22 and 23). The cylinder connected to the long gear lever operates gears 1-2 and 5-6. The cylinder that is connected to the short gear change lever shifts gears 3-4 and 7-8. The integrated reverse gear’s shift cylinder (fig. 1 pos. 24) clearly is different from these shift cylinders. Replacement of this cylinder will not be discussed here.
First, the gear change levers should be mounted as described below (fig. 13B). The short gear lever should be mounted on the hollow clutch shaft first, in such a way that the marks on the switch are on the same line with the marks on the gear lever.
This lever’s fixing bolt should first be tightened at 30 Nm, and finally at 46 Nm. Lock the gear change lever with the lock nut and tighten it at 40 Nm.
The long gear change lever is connected using the same procedure, the final
tightening torque of 30 Nm can, however, be used directly.
A new cylinder should be mounted as follows (figs. 14A and 14B):
- Shift the gearbox into neutral.
- Loosen the lock nut on the new cylinder’s rod.
- Mount the cylinder on the fixed pin on the gearbox housing.
- Connect a compressed air line to the shift cylinder’s middle connection point (Neutral) and pressurize the cylinder.
- Turn the yoke until the head can easily be shoved onto the clutch shaft through the gaps in the yoke and the lever.
- Lock the heads and connect the air lines.
Fig. 14A
6.5 Adjusting shift cylinder (long lever)
1. Turn on the ignition.
2. Aerate the AVS system in neutral position by setting the preselector switch to N and pressing down the clutch pedal.
Note 1. The cylinder must remain aerated during adjustment.
2. The gearbox must mechanically be set in neutral.
3. The long gear change lever has a mark that has to correspond to the mark on the clutch shaft.
3. Turn the cylinder towards the long lever.
4. Verify that the gaps in the yoke correspond to the gap in the long lever. If not, the length of the cylinder must be changed.
5. Change is carried out as follows:
Slide away the rubber boot and loosen the lock nut (22 mm). The shaft in the yoke can now be turned so that the gaps correspond.
6. Screw the nut on the yoke (70 Nm) after the length is changed.
7. Mount the fitting bolt that connects the yoke and the lever stress-free (tightening torque 30 Nm).
8. Lock the fitting bolt with a new check nut (tightening torque nut 40 Nm). 9. Slide the rubber boot over the nut and the yoke ridge.
6.6 Adjusting shift cylinder (short lever)
If the shift turret and the shift cylinder are replaced simultaneously, the shift cylinder must be set in advance.
The preset size (350±1.5
mm) is set as follows:
1. Turn on the ignition.
2. Aerate the AVS system in neutral position by setting the preselector switch to N and pressing down the clutch pedal.
Note 1. The cylinder must remain aerated during
adjustment.
2. The gearbox must mechanically be set in neutral.
3. Verifying the size
- The size can be changed by sliding away the rubber boot and loosening the lock nut (22 mm). The shaft in the yoke can now be turned until the correct size is obtained.
- Screw the nut on the yoke (70 Nm). - Slide the rubber boot over the nut
and the yoke ridge.
- Turn the cylinder towards the short lever.
- Turn the short lever, which is not fixed to the clutch shaft, until the gaps in the yoke and the lever are on the same line and the fitting bolt that connects the lever and the yoke can be mounted stress-free at 30 Nm.
- Lock the fitting bolt with a new check nut (tightening torque 40 Nm).
- Clamp the short lever on the clutch shaft by fastening the M10 bolt and nut (tightening torque 46 Nm).
Note The short lever is meant for
one-time use only; it can only be clamped around the clutch shaft once.
6.7 Adjusting outgoing shaft speed sensor (fig. 16A, 16B, 16C)
Adjustment of the outgoing shaft speed sensor (fig. 1 pos. 215) takes place as follows:
- remove the sensor from the gearbox (fig. 16A)
- Measure distance X between the gearbox housing and one of the teeth.
Note that the tooth must be in the centre of the bore.
- Subsequently, measure distance Y (fig. 16B).
- The margin is then X - Y, which should be 1.2±0.4
mm (fig. 16C).
- Adjust, if necessary, the measured margin by replacing the distance washer.
- Mount the sensor without sealing compound.
Fig. 16A
6.8 Adjusting input speed sensor (fig. 17A, 17B)
Adjustment of the input speed sensor (fig. 1 pos. 200) takes place as follows:
- remove the sensor from the gearbox (fig. 17A).
- Measure distance X between the gearbox housing and one of the teeth.
Note that the tooth must be in the centre of the bore.
- Subsequently, measure distance Y (fig. 17B).
- The margin is then X - Y, which should be 0.8+0.2 - 0.35mm.
- Adjust, if necessary, the measured margin by replacing the distance washer.
- Mount the sensor without sealing compound.
Fig. 17A
Figures 18 up to 31 shows the AVS diagram for the different situations
Fig. 18 Gearbox neutral Fig. 19 1 st gear engaged Fig. 20 2 nd gear engaged Fig. 21 3 rd gear engaged Fig. 22 4 th gear engaged Fig. 23 5 th gear engaged Fig. 24 6 th gear engaged Fig. 25 7 th gear engaged Fig. 26 8 th gear engaged Fig. 27 reverse gear engaged
Fig. 28 Emergency control position 1 2 nd gear engaged Fig. 29 Emergency control position 2 4 th gear emgaged Fig. 30 Emergency control position N gearbox neutral Fig. 31 Emergency control position R reverse gear engaged
Fig. 19 1e
Fig. 20 2e
Fig. 21 3e
Fig. 22 4e
Fig. 23 5e
Fig. 24 6e
Fig. 25 7e
Fig. 26 8e
Fig. 28 Emergency control position 1. 2e
Fig. 29 Emergency control position 2. 4e
8
AVS ERROR TABLE
AVS error messages are described in the following tables. Included are also possible causes, effects on the system, solutions and safety guidelines.
System oriented errors cause an error number to show on the display, which can be viewed according to the procedure Default drive program in chapter 4.6.
8.1 Pneumatic/mechanical errors:
Error Possible cause Solution
Rattling or chattering during shifting.
Clutch switch incorrectly adjusted or defective.
Use emergency switch to go to nearest repair shop
Reverse cannot be accessed at first attempt.
- Teeth out of mesh. - Air pressure too low.
- Reverse engaged while vehicle is moving.
- Shift into reverse again.
- Increase air pressure. - Stop vehicle and turn
rotary switch to "R" again.
One or more gears cannot be used.
- Air pressure too low. - System defective. - Clutch does not
disengage fully
- Increase air pressure. - Use emergency
switch to go to nearest repair shop. - Follow directions
given by vehicle manufacturer. No feedback signal to clutch
pedal.
- Clutch pedal not held down.
- Pressure sensor defective.
- Air pressure too low.
- Press pedal completely down during shifting and keep it there until feedback signal can be felt in the pedal. - Find repair shop.
Normal driving is possible. Release clutch when display shows new gear. - Check air pressure.
Error Possible causes Solution Engine cannot be started using
emergency switch.
- Emergency switch is not in position "N". - Fuse defective.
- Turn emergency switch to position "N".
- Replace fuse. Gears cannot be selected with
emergency switch.
- Not enough air pressure.
- Clutch not held down. - Gear position not
sufficiently aerated.
- Increase air pressure. - Depress clutch pedal
completely and keep it depressed during shifting.
- Depress clutch pedal at least 5 sec. in gear position.
Selected gear in emergency switch is too high.
- Neutral position not sufficiently aerated (range group still in pos. "fast").
- Depress clutch pedal at least 5 sec. in neutral position.
Engine cannot be started. - Fuse blown.
- Gearbox is in gear.
- Replace fuse. - Shift gearbox into
neutral (use air from external source if necessary). Engine cannot be started using
emergency switch.
- Emergency switch not in position "N". - Fuse defective.
- Turn emergency switch to "N".
- Replace fuse. Gear cannot be selected using
emergency switch.
- Air pressure too low. - Clutch not held down. - Gear position
insufficiently aerated.
- Increase air pressure in air receiver. - Depress clutch pedal
completely and keep it depressed during shifting.
- Depress the clutch at least 5 sec. in gear position.
8.2 Electric/electronic errors:
Display Error nr.
Effect on system Action by driver
Safety guidelines
N 35,55 No feedback signal to clutch pedal. Driving can be continued. Follow directions on display.
Press clutch pedal when new gear is displayed.
N 62,63,
64,65
Gearbox doesn’t shift gears; when in reverse: teeth out of mesh.
Check air pressure. If necessary: continue driving with default drive system.
N 75,76 Gearbox doesn’t change gears. Use emergency switch to drive to nearest repair
shop.
N 91,92,
93
No effects. Driving can be continued.
Have errors repaired. 34,54 Default drive light is constantly
burning or doesn’t work.
Driving can be continued. Have errors repaired. 71,72,
73,74
AVS drive program not optimally adjusted.
Driving can be continued. Have errors repaired.
77 Driving signal is not present. Driving can be continued. Shifting down only allowed to maximum nominal rpm.
78 Driving signal not present. Longer delay when shifting to starting gear.
Driving can be continued.
Reverse gear can only be selected/deselected while stationary and when ignition is on.
N 84 Defective control device. Continue driving if possible.
Shifting down only allowed to maximum nominal rpm.
N 88 Default drive program is active. Control (refer to chapter 4).
N 21 Starting gear cannot be selected. Use emergency system to find nearest repair
shop.
N 23 1stand 5thgear cannot be selected. Driving can be continued with manual preselection.
Warning! 1st
gear cannot be selected as starting gear.
N 24 2ndand 6thgear cannot be
selected.
Driving can be continued with manual preselection.
Warning! 2ndgear cannot be selected as starting gear.
N 25 3rdand 6thgear cannot be
selected.
Driving can be continued with manual preselection.
N 26 4thand 8thgear cannot be
selected.
Driving can be continued with manual preselection.
Display Error nr.
Effect on system Action by driver
Safety guidelines
N 31 Applicable only for compression
retarder via AVS:
Engine cannot be shut of with retarder.
Shut off engine: refer to par. 5.5.2 B. Warning! Shift down early when going downhill.
N 32,52 Applicable only for ignition blocking via AVS system:
Engine cannot be shut off via ignition lock.
Shut off engine: refer to par. 5.5.2. B.
N 36 No function "clutch hold-down". Wait for feedback signal to clutch pedal. Warning! If the pedal is released before the pulse, the clutch will not engage. The displays shows "KU".
N, stop, 51 Applicable only for compression retarder via AVS system: - No retarder function. - Engine cannot be shut
off with retarder. - Retarder remains active
all the time.
- Shift down early if going downhill.
- Shut off engine: refer to par. 5.5.2. B.
- To move vehicle out of danger zone: pull plug from retarder valve.
Warning: follow vehicle manufacturer’s instructions.
N, stop, 28,41, 43,44, 45,46, 47,48
Gearbox doesn’t shift gears. Use emergency switch to go to nearest repair shop.
N, stop, 56 Clutch will not engage in certain circumstances. Gearbox does not shift gears.
- Clutch engages: use emergency switch to go to nearest repair shop.
- Clutch does not engage: driving cannot be continued. Let vehicle be towed.
N, stop, 61,67 No display message if clutch pedal is pressed.
Display shows "KU" when clutch is not pressed down.
Check air pressure.
Continue driving with default drive program if necessary.
N, stop, 81 Gearbox does not shift gears. Use emergency switch to drive to nearest
repair shop if no gear is selected after switching the ignition off/on.
