Automatic Transmission/Transaxle: Testing and Inspection

DIAGNOSIS AND TESTING - HYDRAULIC PRESSURE TEST - 45RFE/545RFE

An accurate tachometer and pressure test gauges are required. Test Gauge C-3293-SP has a 300 psi range and is used at all locations where pressures exceed 100 psi.

Pressure Test Port Locations





Only two pressure ports are supplied on the transmission case. The torque converter clutch apply and release ports are located on the right side of the transmission case.





To determine the line pressure, there are two available methods. The DRB scan tool can be used to read line pressure from the line pressure sensor. The second method is to install Line Pressure Adapter 8259 into the transmission case and then install the pressure gauge and the original sensor into the adapter. This will allow a comparison of the DRB readings and the gauge reading to determine the accuracy of the line pressure sensor. The DRB line pressure reading should match the gauge reading within ±10 psi.

Pressure Tap Locations:

In order to access any other pressure tap locations, the transmission oil pan must be removed, the pressure port plugs removed and Valve Body Pressure Tap Adapter 8258-A installed. The extensions supplied with Adapter 8258-A will allow the installation of pressure gauges to the valve body.

TEST PROCEDURE

All pressure readings should be taken with the transmission fluid level full, transmission oil at the normal operating temperature, and the engine at 1500 rpm. Check the transmission for proper operation in each gear position that is in question or if a specific element is in question, check the pressure readings in at least two gear positions that employ that element. Refer to the Hydraulic Schematics to determine the correct pressures for each element in a given gear position. Diagrams

NOTE: The 45RFE utilizes closed loop control of pump line pressure. The pressure readings may therefore vary greatly but should always follow line pressure.

Some common pressures that can be measured to evaluate pump and clutch performance are the upshift/downshift pressures and the garage shift pressures. The upshift/downshift pressure for all shifts is 120 psi. The garage shift pressure when performing a N-R shift is 220 psi. The garage shift pressure for the R-N and N-1 shifts is 120 psi.