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Checking hydraulic pressure

Checking hydraulic pressure


The hydraulics are tested by measuring the system pressure in D and R positions at idling and stalling speeds. The test indicates the condition of the transmission.


1. Put chocks under all 4 wheels.

2. Apply the handbrake fully.

3. Remove the test plug (for B5) from the gearcase and connect an oil pressure gauge.

4. Press the brake pedal down hard.


5. Start the engine and check the idling speed (825 rpm).

6. Fully depress the footbrake and select D or R and check the system pressure against the values in the table.

Position

Idling

Stalling speed

D

3.4 - 3.9 bar

13.1 - 14.2 bar

R

5.1 - 6.2 bar

17.4 - 20.2 bar



Important

Do not run for longer than 5 seconds when testing as the oil temperature can rise above the permitted level. Wait at least 1 minute between tests.


Check that no leaks arise while the oil pressure gauge is connected.

Results of hydraulic test

Fault reason

Pressure greater than value specified above for both D and R

- Faulty SLT

- Fault with voltage to valves

Pressure lower than value specified above for both D and R

- Faulty SLT

- Fault with voltage to valves

- Fault with oil pump

- Fault with brake B5

- oil leakage in hydraulic circuit for D or R

Pressure lower than value specified above for D

- Insufficient system pressure

- Fault with C1

Pressure lower than value specified above for R

- Fault in hydraulic circuit for R

- Fault with C2

- Fault with brake B3