System Pressure And Stall Speed, Check

System pressure and 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
See Checking the oil level Checking Oil Level.

Manometer connection




Ignition off.
Remove the battery and battery tray.
Remove the test plug from the transmission and fit nipple 999 5074 NIPPLE 999 5074 NIPPLE.
Connect the hose and manometer 999 2531 MANOMETER 999 2531 Manometer to the nipple.
Install the battery tray and battery.

Idle speed check
Start the engine and allow it to idle with the selector lever in position N.
Check idle speed. See the table below.

System pressure check
Depress the brake pedal.
Move the selective levers to the various gears and read off system pressure.






Checking stall speed
Check stall speed in conjunction with a system pressure check.
The check primarily provides information on the condition of the torque converter, transmission clutches and the engine.

The following is necessary to ensure correct test results:
- the engine provides full output
- system pressure is correct
- the transmission has the correct oil level and operating temperature

Note! Never check stall speed when system pressure is low.

Check
Connect a tachometer so that it can be read from the driver's seat.
Air conditioning (AC) should be off. Place chocks behind all four wheels. Start the engine.

Caution! Apply the handbrake and depress the brake pedal hard with your left foot during the check.

Move the selector lever to D , apply full throttle max 5 seconds and read off the highest rpm as well as system pressure. Compare with the table below.

Note! The stall speed check must not last more than 5 seconds.





Repeat the check with the gear selector in R.
Compare with the table.
If the rpm exceeds the table values, see High stall speed ; if speed is below the table values, see Low stall speed .

High stall speed
Conditions of element Checking stall speed above are fulfilled. Is the acceleration time for 0-100 km/h (0-60 mph) normal?
If the actual stall speed exceeds the normal value by more than 300 rpm:
- Check if the oil is discolored or has a foul odor. See Oil, quality check Oil, Quality Check.
If the oil is OK , replace the torque converter. See Removing the transmission Transmission, Removal and Transmission, installing Transmission, Installation. (See the procedure regarding torque converter replacement.)
Dirty oil indicates worn or burned clutch discs; replace the transmission. See Removing the transmission Transmission, Removal and Transmission, installing Transmission, Installation.
Recheck stall speed after transmission replacement.

Low stall speed




Conditions of element Checking stall speed above are fulfilled.
If the actual stall speed falls below the normal value by more than 300 rpm, try a new torque converter. See Removing the transmission Transmission, Removal Transmission, installing Transmission, Installation.
Recheck stall speed after torque converter replacement. If the fault remains, replace the transmission. See Removing the transmission Transmission, Removal Transmission, installing Transmission, Installation.
Noise:

Replace the transmission:
Replace the transmission as described in Removing the transmission Transmission, Removal Transmission, installing Transmission, Installation.
Recheck stall speed after transmission replacement.

After completion of the check:
Ignition off.
Remove the battery and battery tray.
Remove the manometer connection and the manometer.

Install:
- the test plug. Check that the O-ring is fault-free; replace as necessary. Tighten to 8 Nm
- the battery tray and battery.