Transmission troubleshooting
INSTRUCTIONS FOR THE IDENTIFICATION OF FAILURES IN HYDROSTATIC TRANSMISSIONS
FAILURES
POSSIBLE CAUSE
CHECK
LOCATION
CORRECT VALUES
The ma-
chine does
not move
neither
forward
nor reserve
Oil Level is low
Oil level
Oil tank
Suction hose is bent or squashed
Suction hose
Hydraulic oil cartridge is clogged
Depressor marked in vacuum
gauge
Suction filter
< 0,3 bar
Faulty coupling
Motor or pump coupling
Pre-load pump turns counterwise to
engine
Load pressure
Pressure intake with a gauge on
pump sport M3 (SAUER GROUP) or S
(BOSCH REXROTH GROUP)
20 ÷ 24 bar
Faulty pre-load pump
Faulty oil motor
Directional solenoid does not work
Resistance and voltage Con-
trol box (SAUER)
Directional solenoids in pump
Inching is seized, disconnected or badly
set (SAUER)
Throw and connections
Pedal and electric connections
Faulty oil strainer
Faulty oil suction Seadling of
tubes connectors and suction
Oil connections
Non instant
motion
response,
abnormal
Oil is air emulsified or Oil level is low
Oil level seating of pipes /
hoses, fittings
Oil tank, fittings
Vacuum filter is clogged
Depressor marked in vaccum
gauge
Vacuum filter
< 0,3 bar
Inching is seized, disco meeted or badly
connected (SAUER)
Potentionmeter, linkage and
connections
Pedal and electric connections
INSTRUCTIONS FOR THE IDENTIFICATION OF FAILURES IN HYDROSTATIC TRANSMISSIONS
FAILURE
POSSIBLE CAUSE
CHECK
LOCATION
CORRECT VALUES
Engine is
overloaded
Low engine power or faulty engine
Engine does not accelerate at
max. Load
Engine
85 ÷ 95 % max rpm. of
engine
High pressure limit is set too low
Working pressure
Working pressure ports in pump
Recommended max. Pressu-
re 345 or 410 bar.
Inching is seized (SAUER)
Potentiometer / linkage
Pedal
< 0,3 bar
Low trac-
tion power
Engine does not work at nominal level or
it’s over
Haul of accelerator lever
Engine
85 ÷ 95 % max rpm. of
engine
Low load pressure
Load pressure
Pressure intake with a gauge on
pump sport M3 (SAUER GROUP) or S
(BOSCH REXROTH GROUP)
20 ÷ 24 bar.
Inching is seized (SAUER)
Potentiometer / linkage
Pedal
M4, M5 (SAUER) or Xa, Xb (BOSCH
REXROTH) Piloting hoses of hydrostatic
motor are reversed.
Hydraulic chart
Connections
Hydraulic Oil overheating
Dirt in radiator
Radiator oil
Hydraulic
oil over-
heating
Low oil level
Oil level
Oil tank
Faulty oil
Oil degradation an pollution
Suction line is not sealed
Sealing for hoses, fitchings
and cartridge
Oil connections
Faulty high pressure relief valves
Working pressure
Working pressure ports in pump
Recommended max. Pressu-
res 345 or 410 bar.
Radiator is dogged
Dirt in radiator
INSTRUCTIONS FOR THE IDENTIFICATION OF FAILURES IN HYDROSTATIC TRANSMISSIONS
FAILURE
POSSIBLE CAUSE
CHECK
LOCATION
CORRECT VALUES
Transmis-
sion overs-
peed
Max. Engine RPM is higher than recom-
mended
Max. RPM on the engine
Engine
Faulty hydrostatic motor. Does not move
to max. flow.
Irregular
running
M4, M5 (SAUER) or Xa, Xb (BOSCH
REXROTH) Piloting hoses of hydrostatic
motor are reversed.
Hydraulic Chart
Oil connections
Insuficient
accelera-
tion
Low engine power
Haul of accelerator lever
Engine
M4, M5 (SAUER) or Xa, Xb (BOSCH
REXROTH) Piloting hoses of hydrostatic
motor are reversed.
Hydraulic Chart
Oil connections
C 400 H / C 400 HI / C 400 H x4 / C 400 HI x4
C 500 H / C 500 HI / C 500 H x4 / C 500 HI x4
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