247
Service.
AUDI A2 - Engine and Gearbox
Design and Function
For internal use only.
Self-study programme 247
2
Contents
Overview
Engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.4 l - TDI (55 kW) AMF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.4 l - 16 V (55 kW) AUA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Gearbox . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Engine
Design and function of the 1.4 l - 16 V engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
System overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Lambda control of the Euro-On-Board Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . 21
Functional overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Page
Gearbox
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Housing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Gearbox design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Double synchronisation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Gear shifting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Actuators and sensors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
The self-study programme will provide you with information on
design and functions.
It is not intended as a workshop manual!
For maintenance and repairs please refer to the current technical
literature.
New
Attention
Note
3
Overview
Engine
1.4 l - TDI (55 kW) AMF
Technical data
Engine code: AMF
SSP247_071
70
63
56
49
42
35
Power output [kW]
28
21
14
7
0
10000 2000 3000 4000 5000 6000
Firing order: 1 - 2 - 3
200
180
160
140
120
100
Torque [Nm]
80
60
40
20
0
SSP247_072
Design: Turbocharged three-
cylinder in-line engine
Capacity: 1422 cm
3
Power output: 55 kW (75 PS)
at 4000 rpm
Torque: 195 Nm at 2200 rpm
Bore: 79.5 mm
Stroke: 95.5 mm
Compression: 19.5 : 1
Weight: 130 kg
Please refer to SSP 223 for the design
and function of the 1.4 l TDI pumpnozzle engine.
Mixture Direct injection with
induction: pump-nozzle unit
Turbocharger: Garrett GT 12 turbocharger
with wastegate
Exhaust emissions Oxidising catalytic
control: converter and exhaust gas
recirculation
Exhaust emissions standard:EU 3
Fuel: Diesel, cetane rating at
least 49 CN, RME
The engine code and engine number are
located on the front engine/gearbox flange.
4
SSP247_026
1.4 l - 16 V (55 kW) AUA
70
200
Technical data
Engine code: AUA
SSP247_001
63
56
49
42
35
Power output [kW]
28
21
14
7
0
10000 2000 3000 4000 5000 6000
Firing order: 1 - 3 - 4 - 2
180
160
140
120
100
80
60
40
20
0
SSP247_002
Torque [Nm]
Design: Four cylinder in-line engine
Petrol engine
Capacity: 1390 cm
3
Power output: 55 kW (75 PS)
at 5000 rpm
Torque: 126 Nm at 3800 rpm
Bore: 76.5 mm
Stroke: 75.6 mm
Compression: 10.5 : 1
Weight: 90 kg
Mixture Electronic, sequential
induction: multipoint injection,
adaptive idlecontrol,
deceleration fuel cut-off
Ignition system: Distributorless ignition
system with static highvoltage distribution, longlife spark plugs
Exhaust emissions
control: 3-way catalytic converter,
2 heated lambda probes,
activated charcoal filter
Exhaust emissions
standard: EU 4
Fuel: Petrol, unleaded, 95 RON
SSP247_069
– Lambda control with probes
upstream and downstream of the
catalytic converter
– Electric exhaust gas recirculation
valve
– Valve actuation via rocker arms
5
Overview
Gearbox
02T gearbox
SSP247_073 SSP247_074
The 02T gearbox is an extremely lightweight
two-shaft gearbox. The parts of the housing
are made of magnesium.
02J gearbox
The familiar 02J gearbox is used in the A2 1.4 l
TDI, for torques up to 250 Nm.
It is designed to transmit torque values of up
to 200 Nm.
Both gearboxes are actuated via gear selector cables and gate
selector cables.
SSP247_075 SSP247_076
6
Design and function of the
1.4 l - 16 V engine
The cylinder block
Engine
The cylinder liners are made of cast iron. They
are cast into the crankcase and can be
reworked.
is made of die-cast aluminium.
The required stiffness is achieved by
pronounced ribbing, and is further reinforced
by the crankshaft bearing blocks.
G12 is the only approved coolant
additive.
As well as preventing frost damage on
the aluminium housing, it prevents the
formation of lime deposits and damage
due to corrosion in the coolant
channels.
The crankshaft
The webs with the cast cylinder liners have a
thickness of 5.5 mm.
SSP247_003
is made of cast iron and is equipped with four
balancer weights. Despite this weight saving,
the crankshaft has the same running
characteristics as crankshafts with eight
balancer weights.
The bearing blocks support the internal
stiffness of the aluminium cylinder block.
The crankshaft must not be loosened or
removed.
If the bearing cap bolts are released
then the internal structure of the
bearing blocks in the cylinder blocks
slackens and causes them to warp.
The bearing clearance is then reduced.
SSP247_004
If the bearing cap bolts are released
then the complete crankcase with
crankshaft needs to be replaced.
It is not possible to measure the bearing
clearance of the crankshaft using
standard workshop equipment.
7
Engine
t
Camshaft drive
The two camshafts are driven by two toothed
belts.
Due to the narrow width of the cylinder head,
the toothed belt drive is divided into a main
drive and a coupled drive.
Coolant pump
Main drive
The main toothed belt drive transmits the
drive from the crankshaft to the coolant pump
and the intake camshaft. An automatic
tensioning roller and two idler rollers prevent
the toothed belt from vibrating.
Coupled drive
The toothed belt of the coupled drive is
located directly behind the toothed belt of the
main drive, outside the camshaft housing.
The coupled drive transmits the drive from
the intake camshaft via the toothed belt to the
exhaust camshaft.
belt pulley
Toothed belt
- main drive
Idler roller
Main drive
tensioning
roller
Intake camshaft
toothed belt
sprocket
Toothed belt coupled drive
Tensioning roller
for coupled drive
Idler roller
Crankshaft
toothed belt
sprocket
SSP247_005
Coupled
drive
Exhaust camshaft
toothed belt sprocke
Here again an automatic tensioning roller
prevents the toothed belt from vibrating.
Guide holes are provided in the
camshaft housing and at the camshaft
toothed belt sprockets for assembly and
for adjusting the valve timing. The two
toothed belt sprockets are secured with
a special tool.
Please refer to the repair manual for
more details.
SSP247_006
Guide holes
SSP247_007
8
Valve gear
The intake camshaft and the exhaust
camshaft run on bearings in the camshaft
housing.
At the same time the camshaft housing also
acts as the cylinder head cover.
The camshafts run on 3 bearings and are
pushed into the camshaft housing.
The axial clearance is limited by the camshaft
housing and the blanking plugs.
The liquid sealer must not be applied
too liberally, as excess material can
enter the oil bores and cause engine
damage.
Intake
camshaft
Cylinder head
Blanking cap
Exhaust
camshaft
Camshaft housing
SSP247_008
Exhaust
camshaft
Cylinder head
Valve actuation
In this generation of engines, the valve
actuation and the valve clearance
compensation are provided by means of a
rocker arm with a hydraulic support element.
Advantages
– reduced friction
– less weight to move
Design
Hydraulic support
element
Roller bearing
of cam roller
The rocker arm consists of a pressed metal
lever and a cam roller with roller bearing.
It is clipped in at the support element and laid
onto the valve.
SSP247_009
Camshaft
Cam roller
Rocker arm
Valve
SSP247_010
9
Engine
Hydraulic support element
Design
Piston with
bore
The support element consists of:
– a piston
– a cylinder and
– a piston spring
It is connected to the engine oil circuit. A
small ball with a spring forms a one-way valve
in the lower oil chamber.
Function during valve clearance
compensation
In the event of excessive valve clearance the
piston is pushed out of the cylinder by the
piston spring until the cam roller lies up
against the cam. While it is being pushed out
the oil pressure in the lower chamber
reduces.
The one-way valve opens and oil flows in.
Oil channel
Piston spring
One-way valve
Cylinder
Upper
oil chamber
Lower
oil chamber
SSP247_011
Valve clearance
Once the pressure difference between the
lower and upper oil chamber has been
equalised the one-way valve closes.
Valve lift
When the cam runs onto the cam roller the
pressure in the lower oil chamber increases.
The trapped oil cannot be compressed, which
means that the piston cannot be pushed any
further into the cylinder.
The support element becomes a rigid
element which acts as a support for the
rocker arm.
The corresponding valve opens.
SSP247_012
SSP247_013
10
Lubrication
is provided via the hydraulic support element.
The rocker arm has a bore through which oil
is sprayed onto the cam roller.
Oil bore in the
support element
Oil channel in the
cylinder head
Function during valve actuation
The support element acts as a pivoting point
for the motion of the rocker arm. The cam
runs on the cam roller and presses the rocker
arm downwards. The valve is then actuated
via the rocker arm.
Oil
Cam roller
SSP247_014
Cam
Cam roller
The lever arm between the cam roller and the
support element is shorter than between the
valve and the support element. This means
that a relatively small cam can achieve a large
valve lift.
The hydraulic support elements cannot
be checked.
Rocker arm
SSP247_015
11
Engine
Electric exhaust gas recirculation valve
EGR valve N121
Exhaust
manifold
EGR valve N121 is electrically controlled and
actuated directly by engine control unit J537.
Pressure equalisation
Supply line to
intake manifold
SSP247_016
A stainless steel pipe connects the valve with
the intake manifold.
The valve is flanged directly onto the cylinder
head and directly connected to the exhaust
duct of cylinder no. 4 by means of a channel
in the cylinder head.
12
The high temperatures caused by the exhaust
gases are transferred to the cylinder head and
cooled by the coolant flowing through.
Functional diagram
Air cleaner
Intake manifold
N121
G212
J537
t
°C
n
1/min
p
MPa
Even in normal operation of the engine a
certain amount of residual gas leaks from the
combustion chamber into the intake manifold
when the valves are rocking.. In the
subsequent induction process a proportion of
the residual gas is then drawn in with the
fresh mixture (internal exhaust gas
recirculation).
Up to a certain degree the residual gas
(exhaust gas) can have a positive effect on
reducing the amount of nitrogen oxides in the
exhaust, and it can help to convert energy
more efficiently (reduced fuel consumption).
The additional exhaust gas recirculation helps
to reduce NO
emissions (nitrogen oxides)
x
further and to lower fuel consumption.
To do this, a certain amount of exhaust gas is
taken and fed back to the intake air via EGR
valve N121. This is called “external” exhaust
gas recirculation.
Supply line to
intake manifold
Engine load
SSP247_017
In order to optimise the distribution of
recirculated exhaust gas and induced fresh
air, the exhaust gas emerges into the fresh air
flow directly under the middle of the throttle
valve, at two holes positioned at right angles
to the intake air flow.
EGR valve N121 is actuated by engine control
unit J537 according to a defined map. It takes
information such as engine speed, engine
load, air pressure and coolant temperature
into account.
EGR potentiometer G212 informs the engine
control unit of the cross-section of the
opening.
With the exhaust gas recirculation active the
amount of gas that can be recirculated is
limited to 18 % of the intake air quantity.
There is no exhaust gas recirculation in idle,
in overrun or during engine warm-up up to
o
35
C
13
Engine
Function
Potentiometer
Anchor
Coil
Exhaust gas
from engine
Pressure
equalisation
via air cleaner
The EGR valve terminates (zero-current
process) the recirculation of exhaust gases to
the intake manifold. It is switched on from a
coolant temperature of 35
When it is actuated, the valve is opened with
a defined duty cycle.
The input information includes
– information about the engine speed
– information about the load status of the
engine
– coolant temperature
– air pressure
A potentiometer is located in the valve head.
This potentiometer detects the opening
cross-section of the valve, which is passed
back as a return message to the engine
control unit. The opening cross-section is
then used to control the voltage of the coil in
the valve according to the map.
o
C.
Valve
Electrical circuit
To intake
manifold
SSP247_018
SSP247_019
A direct connection to ambient air pressure is
provided via the air cleaner to allow for
pressure equalisation in the valve during the
different control phases.
Diagnostics
The valve has diagnostic capabilities.
The following are stored in the fault memory:
– Zero point shift
– Maximum opening
– Maximum path
It is also detected if a valve is sticking.
G212 EGR potentiometer
J537 Control unit for 4LV
N121 Frequency valve for exhaust gas
recirculation
14
The fuel pump located inside the fuel tank
pumps fuel through the fuel filter to the
injectors.
Operating breather
container
Gravity valve
Fuel filter
Fuel pump G6
Fuel pressure
regulator
Distribution rail
Activated
charcoal filter
Solenoid valve for ACF
system N80
Injectors N30 … N33
The A2 is equipped with a safety fuel shut-off
system for the event of a crash, as described
in SSP 207.
SSP247_020
Intake manifold
15
Engine
Overview of system
Intake manifold pressure sender G71
with
Intake air temperature sender G42
Engine speed sender G28
Versions I and II
Hall sender G40
Knock sensor I G61
Lambda probe upstream of catalytic
converter G39 with
Heater for lambda probe Z19
Lambda probe downstream of
catalytic converter G130 with
Heater for lambda probe Z29
Control unit for 4LV
J537
Coolant temperature sender G2/G62
Throttle valve control part J338 with
Throttle valve drive G186 (electric
throttle operation)
Angle sender 1/2 for throttle valve
drive G187/G188
Accelerator pedal module with accelerator
pedal position sender G79/G185
Brake light switch F/F47
Auxiliary input signals
A/C compressor
Air conditioner (engine speed increase)
Tank fill level*; crash signal; CCS switch; DF signal; vehicle
speed signal from combi-processor J218
Diagnostic
connection
16
Ignition transformer N152
Injectors N30, N31, N32, N33
Fuel pump relay J17
Fuel pump G6
Control unit for
ESP J104
P
M
E
T
F
F
O
Air conditioner control
and display unit E87
Combi-processor in
dash panel insert J218
Solenoid valve I for
ACF system N80
Throttle valve drive G186
with
throttle valve positioner V60
EGR valve N121
Sender for
steering angle
G85
* discontinued as of
CAN compatible
combi-processor J218
SSP247_021
Heating resistor N79
(crankcase breather)
Auxiliary output signals
Engine speed signal*
A/C compressor
17
Engine
Engine speed sender G28
The sender is a combined speed sender and
reference mark sender.
Two different sealing flange systems and
sender versions are in use.
Crankshaft
Elastomer gasket
Sender wheel
Engine speed
sender G28
Sealing flange
Gasket
Sealing flange
Sealing is provided at the crankshaft.
Crankshaft
Sender wheel
Sender wheel
SSP247_078
18
J448
Engine speed
sender G28
Crankshaft
Sender wheel
G28
SSP247_080
Crankshaft
Sender wheel
Sealing flange
Sealing flange
Sender wheel
SSP247_079
Application of the signal
The signal from the engine speed sender is
used to detect the engine speed and the
exact position of the crankshaft. The engine
control unit uses this information to
determine the timing of injection and
ignition.
The effect of a signal failure
The engine control unit switches to
emergency running mode if the engine speed
sensor fails. The control unit then calculates
the engine speed and camshaft position from
information provided by camshaft position
sender G163.
The maximum engine speed is lowered in
order to protect the engine. It is still possible
to restart the engine.
19
Engine
The Hall sender G40
is located at the camshaft housing above the
intake camshaft.
Three teeth are cast onto the intake camshaft,
where they are scanned by the Hall sender.
Application of the signal
The signal is used together with the signal
from the engine speed sender to detect
ignition TDC on cylinder no. 1. This
information is required for the cylinderselective knock control and the sequential
fuel injection.
The effect of a signal failure
In the event of sender failure the engine
continues to run and can also be restarted.
The engine control unit goes into emergency
running mode. The fuel injection then
switches from sequential to parallel mode.
J537
G40
SSP247_029
Hall sender G40
20
Blanking cover
SSP247_030
Intake camshaft with
cast-on sender wheel
Camshaft housing
Lambda control of the
Euro-On-Board-Diagnosis
The new broadband lambda probe is used as
a pre-cat probe in conjunction with the EOBD.
An almost linear current increase is used for
the output of the lambda value. As a result
the lambda value can be measured over the
entire engine speed range.
Function
With the broadband lambda probe, the
lambda value is calculated from a change in
current rather than a change in voltage.
However, the physical processes are the
same.
Broadband lambda probe
I = current
SSP247_022
Planar lambda probe
The familiar planar lambda probe is used as
the post-cat probe.
The measuring range fluctuates erratically
around the value lambda = 1 and is sufficient
for monitoring purposes.
Broadband lambda probe
U = voltage
Planar lambda probe
SSP247_023
SSP247_083
21
Engine
Broadband lambda probe
This probe uses two electrodes to generate a
voltage relating to the varying oxygen content
of the exhaust gas.
The voltage at the electrodes is kept constant.
This process is achieved by means of a
miniature pump (pump cell), which supplies
the electrode on the exhaust side with
enough oxygen to keep the voltage between
the two electrodes at a constant value of 450
mV. The engine control unit converts the
current consumption of the pump into a
lambda value.
7
5
6
8
9
1
4
1 Fresh air
2 Probe voltage
3 Engine control unit
4 Electrodes
5 Exhaust gas
6 Miniature pump (pump cell)
7 Pump current
8 Measuring range
9 Diffusion channel
3
2
SSP247_024
22
Exhaust gas
6
1
5
4
3
2
SSP247_025
1 Oxygen pump cell
2 Nernst cell (two-point probe)
3 Probe heater
4 Fresh air (reference air)
5 Measuring range
6 Diffusion channel
If the fuel/air mixture becomes too rich then
the oxygen content of the exhaust gas drops.
The pump cell pumps less oxygen into the
measuring area and the voltage rises at the
electrodes.
In this case more oxygen escapes through the
diffusion channel than is pumped by the
pump cell.
The pump cell has to increase its pumping
rate to make the oxygen content in the outer
air chamber rise. This regulates the electrode
voltage back to the value of 450 mV, and the
engine control unit then converts the current
consumption of the pump into a lambda
value.
SSP247_027
If the air/fuel mixture is too lean then this
function is reversed.
The pumping effect of the pump cell is a
purely physical process. A positive
voltage at the pump cell attracts
negative oxygen ions through the
ceramic, which is permeable to oxygen.
SSP247_028
The linear lambda probe and the engine
control unit form a system together. The
lambda probe must match the engine
control unit.
23
Engine
Functional diagram
Key
1.4 l - 16 V (55 kW) AUA
Components
E45 CCS switch
E227 Button for cruise control system
F Brake light switch
F36 Clutch pedal switch
F47 Brake pedal switch
G6 Fuel pump
G28 Engine speed sender
G39 Lambda probe upstream of
catalytic converter
G40 Hall sender
G42 Intake air temperature sender
G61 Knock sensor I
G62 Coolant temperature sender
G71 Intake manifold pressure sender
G79 Accelerator pedal position sender
G130 Lambda probe downstream of
catalytic converter
G185 Accelerator pedal position
sender 2
G186 Throttle valve drive
(electric throttle operation)
G187 Angle sender 1 for throttle valve
drive (electric throttle operation)
G188 Angle sender 2 for throttle valve
drive (electric throttle operation)
G212 EGR potentiometer
J17 Fuel pump relay
J218 Combi-processor in dash panel
insert
J338 Throttle valve control part
J537 Control unit for 4LV
M9/10 Bulb for left/right brake light
N30 … 33 Injectors, cylinders 1 … 4
N79 Heating resistor (crankcase
breather)
N80 Solenoid valve for ACF system
N121 Frequency valve for exhaust gas
recirculation
N152 Ignition transformer
P Spark plug connector
Q Spark plugs
Z19 Heater for lambda probe
Z29 Heater for lambda probe 1,
downstream of catalytic converter
Colour coding
= input signal
= output signal
= battery positive
= earth
= CAN-BUS
= bi-directional
= diagnostic connection
Auxiliary signals
1 Crash signal, airbag control unit
2 Terminal 50 signal, ignition starter
switch
3 Alternator terminal DF
4 Vehicle speed signal
(from combi-processor J218)
5 A/C compressor
(engine speed increase)
6 Tank fill level*
7 TD signal*
8 A/C compressor
CAN-BUS H =
CAN-BUS L =
}
x Connection within the functional
diagram
* discontinued for CAN compatible
combi-processor J218
Databus drive
24
+
15
S20
20A
F36
S31
10A
N79
+
30
3
J17
X
1 2
M
S18
20A
G6
S45
15A
N30
N31
N32 N33
S19
20A
G39 Z19 G130
N80
λ λ
Z29
+
30
S30
10A
X
F
M
3 4 5 6 7 8
CAN - L
CAN - H
F47
J537
X
J338
+
-
o
N152
M
+
-
E45
IIIIV III
Q
P
E227
G79G185
G187G186 G188
N121 G212
X
G40
G28G42 G71
G62
G61
31
in out
Gearbox
Overview
The 5-speed manual gearbox 02T
The 02T gearbox is an extremely lightweight
two-shaft gearbox. The parts of the housing
are made of magnesium. The gearbox can
transmit torques of up to 200 Nm.
26
SSP247_032
This gearbox is used across the range in
conjunction with numerous engines.
Therefore it was important to design the gear
wheel transmission ratios and the final drive
ratio as flexibly as possible.
Engine/gearbox combinations
Manual
Ratio i = No. of teeth on driven wheel z
2
5-speed gearbox
No. of teeth on driving wheel z
1
Gearbox code EYX EWO
Engine allocation 1.4 l/55 kW 1.4 l/55 kW
z
2
z
1
iz2z
1
i
Final drive 66 17 3.882 61 18 3.389
1st gear 38 11 3.455 34 09 3.778
2nd gear 44 21 2.095 36 17 2.118
3rd gear 43 31 1.387 34 25 1.360
4th gear 40 39 1.026 34 35 0.971
5th gear 39 48 0.813 34 45 0.756
Reverse gear 35
24
24
11
3.182
36
18
20
09
3.600
Speedometer electronic
Gear oil fill capacity 1.9 litres
Gear oil specification G50 SAE 75 W 90
(synthetic oil)
Gear oil change Filled for service life
Clutch mechanism hydraulic
The code letters of the gearbox are also
given on the vehicle data plates.
27
Gearbox
Housing
The gearbox housing consists of
2 magnesium parts (gearbox housing, clutch
housing).
A cover closes off the gearbox housing to the
outside.
Mounting points for engine/
gearbox mountings
The parts of the gearbox housing are
made of magnesium in support of its
lightweight design principles. This
measure alone has led to a weight
reduction of 2.5 kg compared to the
conventional aluminium design..
Gearbox housing
Gearbox housing
cover
Clutch housing
28
SSP247_033
The gearbox has a modular design concept.
Key assemblies:
Clutch release lever
This module contains the release lever, the
release bearing and the guide sleeve.
Selector shaft with selector mechanism cover
This module contains all of the locking
elements, spring elements and guide
elements of the gearshift mechanism.
SSP247_034
Internal selector mechanism (shift
mechanism)
with the selector forks and the selector
plates.
Bearing support
with the two grooved ball bearings and the
pre-assembled input and output shafts.
SSP247_035
SSP247_036
SSP247_056
29
Gearbox
Gearbox design
Reverse idler gear
Gearbox housing
cover
1st/2nd gear are double-synchronised. All the
other forward gears are single-synchronised.
The teeth of the sliding gears and the gear
wheels are helical-cut and constantly
meshed.
All of the sliding gears run on needle roller
bearings.
Gearbox housing
The sliding gears are distributed between the
input shaft and the output shaft
1st and 2nd gear is selected on the output
shaft, 3rd, 4th and 5th gears on the input
shaft.
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The reverse gear is a straight-cut gear.
The reversal of the direction of rotation on the
output shaft is effected with a reverse idler
gear, which sits on a separate shaft in the
gearbox housing and is shifted between the
input shaft and the output shaft.
Torque is transmitted to the
differential via the output gear wheel on the
output shaft to the final drive
gear wheel.
Clutch release lever
Input shaft
Final drive gear wheel
Output shaft
Clutch housing
A wide range of special tools is available
for all repair work involving the removal
and installation of bearings, bushes, oil
seals etc.
Please refer to the notes in the repair
manual.
SSP247_038
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Gearbox
Input shaft
The input shaft is designed in the classic
fixed/loose mounting style.
It runs on
– a cylindrical roller bearing (loose) in the
clutch housing and
– a grooved ball bearing (fixed) which is
seated in a bearing unit
in the gearbox housing.
The input shaft has a deep-drilled hole
in order to save weight.
5th gear sliding gear
1st gear
teeth
Bearing unit
with grooved
ball bearing
2nd gear
teeth
Reverse gear teeth
The teeth for 1st gear, 2nd gear and reverse
gear are permanently connected to the input
shaft.
The needle roller bearing for the 5th gear runs
on a sleeve on the shaft side. The needle
roller bearings of the 3rd and 4th gears run
directly on the input shaft.
SSP247_039
3rd gear sliding gear
4th gear sliding gear
Deep-drilled hole for
weight reduction
SSP247_040
Cylindrical roller
bearing
The synchro-hubs for the 3rd/4th gear and the
5th gear are attached via fine teeth.
Circlips keep them in position.
The deep-drilled hole and the hollow
bore in the output shaft have resulted in
a weight reduction of approx. 1 kg.
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Output shaft
The output shaft is also designed in the
classic
fixed/loose mounting style.
Just like the input shaft it runs on
– a cylindrical roller bearing (loose) in the
clutch housing and
– a grooved ball bearing (fixed) which sits
together with the input shaft in the bearing unit
in the gearbox housing.
The output shaft has a hollow bore to reduce
weight.
1st gear sliding
gear
5th gear wheel
2nd gear sliding
gear
3rd gear wheel
SSP247_041
4th gear wheel
Bearing unit
with grooved
ball bearing
The gear wheels for the 3rd, 4th and 5th gears
and the 1st/2nd gear synchro-hub are
attached via fine teeth.
Circlips keep them in position.
Drilled hole for
weight reduction
SSP247_042
Gear teeth to final
drive gear wheel
Cylindrical roller
bearing
The sliding gears of the 1st and 2nd gears run
on needle roller bearings on the output shaft.
The grooved ball bearings for the input
and the output shafts should only be
replaced as a joint bearing assembly.
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Gearbox
Differential
The differential (with flange shafts for the
final drive) forms an assembly with the
manual gearbox.
It runs on two frictionally optimised taper
roller bearings in the gearbox and the clutch
housing.
Sealing rings (different sizes for the left and
right hand sides) seal the housing to the
outside.
The final drive crown wheel is riveted to the
differential housing and paired with the
output shaft (to lower transmission noise).
SSP247_043
The sender wheel for the speedometer is an
integral part of the differential housing.
Output shaft
Final drive gear wheel
Gearbox housing
The differential needs to be adjusted if
any components are replaced that affect
the play of the taper roller bearings. This
is done with a shim in the clutch
housing. Please refer to the repair
manual for further details.
Clutch housing
Differential housing
Shim
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Taper roller
bearing
Taper roller
bearing
Segments for
detection of rotational speed
SSP247_044
Flange shaft
Double synchronisation
1st and 2nd gear are double-synchronised. A
second synchroniser ring (inner) is used with
an outer ring for this double synchronisation.
SSP247_045
The double synchronisation improves the
smoothness of the gear change from 3rd gear
down to 2nd
and from 2nd gear down to 1st.
Thanks to the almost doubling in size of the
tapered frictional surface area, the
effectiveness of the synchronisation is
improved by approx. 50%, and the gear
change effort is reduced by roughly a half.
1st gear sliding gear
Locking collar with
synchro-hub for 1st
and 2nd gear
Sliding gear
Synchroniser
ring (inner)
SSP247_046
2nd gear sliding gear
The double synchronisation consists of:
– a synchroniser ring (inner)
– an outer ring
– a synchroniser ring (outer).
Synchronisation takes place via the two
synchroniser rings and the outer ring.
SSP247_047
Outer ring
Synchroniser
ring (outer)
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Gearbox
Power flow
SSP247_049SSP247_048
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SSP247_051
SSP247_050
SSP247_053SSP247_052
Power flow in the gearbox
The engine torque is transmitted to the
gearbox via the input shaft.
Depending on the selected gear, the torque is
then transmitted to the appropriate pair of
gears on the output shaft, and from here to
the final drive gear wheel and the differential.
SSP247_054
The torque and rotational speed then act on
the drive wheels according to the settings of
the gearshift mechanism.
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Gearbox
Bearing support
The grooved roller bearings are not mounted
directly onto the gearbox housing, and
instead sit in a separate bearing support.
Bearing support
Output shaft
Input shaft
SSP247_056
SSP247_055
The complete package of shafts and gear
wheels for the input shaft and the output
shaft is pre-assembled outside the gearbox
housing in the bearing support, and can then
be easily inserted into the gearbox housing.
A disc shape is used to secure the grooved
roller bearings in installation position. The
disc shape is welded to the bearing support.
The grooved roller bearings have their own
radial oil seals on both sides that keep any
abraded particles suspended in the gear oil
away from the bearings.
The bearing support is pressed into the
gearbox housing with its collar in the shape
of a pair of glasses, and is then attached to
the gearbox housing with six bolts.
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The bearing support is replaced as a
complete unit with the two grooved
roller bearings after repairs.
This is done every time the unit is
dismantled.
Please also refer to the notes in the
repair manual.
Gear selection
Internal shift mechanism
The gear selection movements come into the
gearbox from above.
The selector shaft is guided in the selector
mechanism cover.
For gate selection movements it is moved in
an axial direction.
Two spring-loaded balls prevent the selector
shaft from twisting out of the selected gear
position.
Selector shaft
Shift mechanism
cover
Ball
(not visible)
Angular contact
ball bearing
Selector plate
Selector
segment
SSP247_057
The bearings for the selector forks for 1st/2nd
gear and
3rd/4th gear are angular contact ball
bearings. They help to improve the
smoothness of gear changes.
The selector fork for the 5th gear has a
friction bearing.
The selector forks and selector plates are
loosely
coupled to each other.
When a gear is selected the selector shaft
moves the selector plate with its fixed
selector finger, and the selector plate in turn
moves the selector fork.
The selector segments of the selector forks sit
in the locking collar of the corresponding pair
of gear wheels.
5th gear
selector fork
Reverse gear
selector fork
3rd/4th gear
selector fork
SSP247_058
1st/2nd gear
selector fork
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Gearbox
Adjusting the selector cables
Both the gearshift mechanism housing and
the gearshift mechanism cover have been
fitted with auxiliary devices that make
adjustments to the selector cables a lot
easier.
No measuring operations or templates for
marking positions are required.
The adjustment always begins with the
gearbox in
neutral:
Gear selector
cable
Gate selector
cable
– Loosen the cables:
The securing mechanism on the gear
selector cable and the gate selector cable
is pulled forwards as far as its stop and
then twisted to the left to lock it. The
length of the cables can now be adjusted,
which is performed automatically when
the selector shaft and selector lever are
positioned as follows.
– Lock the selector shaft:
A bracket is attached to the gearshift
mechanism cover which can be used to
secure the selector shaft in a pre-defined
position.
To do this, press the selector shaft
downwards by hand into the 1st/2nd gear
gate, and while pressing down turn the
adjusting bracket in the direction of the
arrow and press it against the selector
shaft. It engages and locks the selector
shaft in this position.
SSP247_059
SSP247_060
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Bracket
Position of the gear lever
during the adjustment process
– Lock the gear lever:
The gear lever is moved into in the 1st/2nd
gear gate with the gearbox in neutral.
The gear lever has a fixed locating lug.
Guide pin T10027 is inserted through the
hole in the lug into the bore in the
gearshift mechanism housing which lies
underneath.
R1 3 5
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SSP247_061
T10027
Guide pin
Locating lug
– Securing the cables:
Now the securing mechanism on the gate
selector cable and the gear selector cable
can be twisted back to the right.
The spring presses the securing
mechanism into the selected position and
secures it.
Now release the bracket again and take
out the guide pin.
The gear lever should now be in the 3rd/
4th gear gate when the gearbox is in
neutral.
SSP247_062
SSP247_063
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Gearbox
Sensors and actuators
Vehicle speed display
The speedometer is driven without any
mechanical intermediate stages.
The information required for the vehicle
speed is taken as a rotational speed directly
from the differential housing by vehicle speed
sender G22.
The differential housing has reference
markings for this purpose, 7 raised segments
and 7 indentations.
Sender for
speedometer G22
The sender operates in accordance with the
Hall sender principle. The PWM signal (pulse
width modulated) is sent to the combiprocessor in dash panel insert J218.
Electrical circuit
Reference markings on the
differential housing
SSP247_064
SSP247_065
J218
D +15 Ignition starter switch, terminal 15
G21 Speedometer
G22 Vehicle speed sender
J218 Combi-processor in the dash panel
insert
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D
+15
G21
G22
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SSP247_066
Reversing light switch F4
The reversing light switch is bolted to the side
of the gearbox housing.
When reverse gear is engaged a ramp with a
defined slope on the reverse gear selector
plate actuates the switch.
The electrical circuit to the reversing lights is
made.
Reversing light
switch F4
Gearbox housing
Ramp
SSP247_067
Reverse gear
selector plate
Electrical circuit
D +15 Ignition starter switch, terminal 15
F4 Reversing light switch
M16 Left reversing light bulb
M17 Right reversing light bulb
D
+15
S7
10A
F4
M17M16
SSP247_068
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247
All rights reserved, including the
right to make technical changes.
AUDI AG
Dept. I/VK-5
D-85045 Ingolstadt
Fax 0841/89-36367
040.2810.66.20
Technical status 03/00
Printed in Germany
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