Clutch Test allows a technician to manually select each of the 6 forward ranges with the vehicle stopped. The intent of this procedure is to verify the ability of all 5 clutches to transmit torque without slipping. Refer to the table in Adapt Function , which shows the clutches applied in each gear range.
Clutch Test
Use the scan tool in order to perform the clutch test. Select the following information when setting up the tool for running the test. Use the Shift Transmission feature on the scan tool to complete the clutch test.
- Select F0: Diagnostics and press ENTER.
- Select Model Year.
- Select LDTrk, MPV, Incomplete.
- Select F0: Powertrain, press ENTER.
- Select Engine size, press ENTER.
- Select 6 Speed Automatic, press ENTER.
- Select F2: Special Functions, press ENTER.
- Select F1: Transmission Output Controls.
- Select Shift Transmission. This allows the technician to shift the transmission and observe the integrity of each clutch/range in the transmission.
Attach the transmission pressure gage as described in the Line Pressure Check Procedure. Refer to Line Pressure Check . Apply the parking brake. Hold the service brakes with your left foot and move the gear selector to DRIVE. Increase engine speed to 1,400 RPM with your right foot. With soft keys, select UPSHIFT and shift the transmission from FIRST gear to SIXTH gear while observing turbine speed. Turbine speed should increase momentarily and then drop to 0 RPM when each gear is attained. Line pressure should drop momentarily, then gain pressure again when each gear is attained.
Maintain 1,400 RPM and select the DOWNSHIFT soft key. Downshift the transmission from SIXTH gear sequentially to FIRST gear while observing turbine speed. Turbine speed should increase momentarily and then drop to 0 RPM when each gear is attained.
To further investigate a suspected leak in a clutch circuit, the clutch test should be repeated, keeping the engine at idle speed. While performing the clutch test at 600 RPM, main pressure should drop momentarily, then gain pressure again when each gear range is attained. If main pressure remains low, suspect damaged seal in that range. If low pressure is in FIRST range only, suspect Low and Reverse piston seal damage.
