Hydraulic Pressure Testing

Pressure testing is only performed in the diagnostic procedure when actuating solenoids for the 42LE. Many times, it can reveal the cause (not the symptom) of most transaxle problems. Hydraulic pressure testing verifies the proper functioning, or malfunctioning, of the following hydraulic components:
- Oil pump
- Regulator valve
- Hydraulic circuits

Transaxle problems can be isolated to an electronic or hydraulic/mechanical component. The hydraulic pressure test is a helpful tool in determining whether the problem is electronic or hydraulic/mechanical.

Though reference must be made to other areas for testing purposes, sequence, pressure tap readings and test results, there are some general guidelines that apply to this procedure, as follows:
- Verify proper fluid level and condition.
- Verify and correct for proper gearshift linkage adjustment.
- Verify that electrical connectors associated with the transaxle are properly connected and are clean and secure.
- Allow the transaxle to reach operating temperature before testing.

Any of the above conditions, if not checked and/or corrected, can result in false readings and inaccuracies.