System Pressure And Stall Speed, Check
Line pressure/stall speed, check
Special tools:
999 2531 MANOMETER 999 2531 Manometer
999 5074 NIPPLE 999 5074 NIPPLE
Note! As the illustrations in this service information are used for different model years and / or models, some variation may occur. However, the essential information is always correct.
Checking the oil level
Check the oil level.Checking Oil Level
Removing the air cleaner (ACL) housing
Ignition off.
Remove the air cleaner housing ACL assembly with the intake pipe. Pull the air cleaner (ACL) housing out of its mountings.
Connecting the manometer
Remove the test plug from the transmission. Install nipple 999 5074 NIPPLE 999 5074 NIPPLE.
Connect the hose and manometer 999 2531 MANOMETER 999 2531 Manometer to the nipple.
Installing the air cleaner (ACL) housing
Install the air cleaner (ACL) housing, including all hoses and electrical terminals.
Checking the engine idling speed
Start the engine. Allow it to idle in neutral.
Check the engine idle speed. See the table below.
Checking the line pressure
Depress the brake pedal.
Move the gear selector into its various positions. Read off the line pressures.
Checking the stall speed
Check the stall speed when checking the line pressure.
The stall speed test gives an indication of the condition of the torque converter, the transmission clutches and the engine.
For the test to be accurate the following conditions must be met:
- the engine must be properly tuned
- the line pressure must be correct
- the oil level in the transmission must be correct and the transmission must be at operating temperature.
Note! Never conduct a stall speed check when the line pressure is too low.
Check
The air conditioning (A/C) must be turned off. Block all four wheels. Start the engine.
Caution! Apply the parking brake. Press down hard on the brake pedal using your left foot during the test.
Move the gear selector to position D. Fully depress the accelerator pedal (AP) for a maximum of 5 seconds. Read off the maximum engine speed (RPM) and the line pressure. Compare to the table below.
Note! Do not test the stall speed for longer than 5 seconds.
Repeat the test with the gear selector in position R.
Compare to the table.
If the engine speed (rpm) exceeds the value in the table, see High stalling speed. If the engine speed (rpm) is less than the value in the table, see Low stalling speed.
High stalling speed
The test conditions described in Check above, have been met. Is acceleration from 0-100 km/h normal?
If the stalling speed recorded exceeds the normal value by more than 300rpm:
Check if the oil is discolored or smells burnt. See Oil grade, checking, B5254T2, AW50/51 AWD, B5254T2, AW55-50/51SN Oil Grade, Checking.
If the oil is OK, replace the torque converter.
For gasoline engines see Gearbox, removing Gearbox, Removing and Installing the gearbox, B5254T2, AW50/51 AWD, B5254T2, AW55-50/51SN Gearbox, Installing.
For diesel engines see and Transmission, installing Gearbox, Installing. (See the procedures that also apply when replacing the torque converter
Dirty oil indicates worn or burnt clutch plates. Replace the transmission.
For gasoline engines see Gearbox, removing Gearbox, Removing and Installing the gearbox, B5254T2, AW50/51 AWD, B5254T2, AW55-50/51SN Gearbox, Installing.
For diesel engines see and Transmission, installing Gearbox, Installing.
Check the stalling speed again after replacing the transmission.
Low stalling speed
The test conditions described in Check above have been met.
Try a new torque converter if the stall speed recorded is below the normal value by more than 300 rpm.
For gasoline engines see Gearbox, removing Gearbox, Removing and Installing the gearbox, B5254T2, AW50/51 AWD, B5254T2, AW55-50/51SN Gearbox, Installing.
For diesel engines see and Transmission, installing Gearbox, Installing.
Check the stalling speed again after replacing the torque converter
Replace the transmission if the fault persists. For gasoline engines see Gearbox, removing Gearbox, Removing and Installing the gearbox, B5254T2, AW50/51 AWD, B5254T2, AW55-50/51SN Gearbox, Installing.
For diesel engines see and Transmission, installing Gearbox, Installing.
Noise:
Replace the transmission:
For gasoline engines see Gearbox, removing Gearbox, Removing and Installing the gearbox, B5254T2, AW50/51 AWD, B5254T2, AW55-50/51SN Gearbox, Installing.
For diesel engines see and Transmission, installing Gearbox, Installing.
Check the stalling speed again after replacing the transmission.
After the check is completed:
Remove the air cleaner housing (ACL) assembly with the intake pipe.
Remove both the manometer connection and the manometer.
Install:
- the test plug. Check that the O-ring is undamaged. Replace if necessary. Tighten to 8 Nm
- the air cleaner (ACL) housing with all hoses and electrical terminals.