Diagnosing GM Converter Lock-Up Problems
Test #8
Checking Cooler Line Pressure or Surge
- Check cooler line pressure or surge.
- Disconnect a cooler line.
- Attach one end of a rubber hose to the disconnected line coming from the radiator.
- Insert the other end of the rubber hose into the fill tube of the transmission.
- With the driving wheels off the ground, start the engine. Hold the rubber hose in your hand. Have as assistant place the selector in Drive and (slowly) accelerate to 60 mph. When the lock-up valve moves, the rubber hose should jump slightly.
Test #9
Checking the Solenoid
You will need an ANALOG ohmmeter and a 12-volt source for this test.
- Connect the Black lead of your ohmmeter to the RED wire on the solenoid.
- Connect the RED lead of your ohmmeter to the BLACK wire on the solenoid. If you have a one-wire solenoid then connect the RED lead of your ohmmeter to the solenoid body.
- With the ohmmeter set at ohms times one (Rx1), the reading should be no less then 20 ohms, but not infinite.
- Connect the RED lead of your ohmmeter to the RED wire on the solenoid and the Black lead to the Black wire or body (You're just switching your connections).
- The ohmmeter should read less than the reading in the first test.
- Connect the solenoid to a 12-volt source. BE SURE TO OBSERVE PROPER POLARITY, if using a car battery.
- With lung pressure (or very low pressure) try to blow through the solenoid. It should be sealed.
- Disconnect the 12-volt source and you should now be able to blow through the solenoid.
Test #10
Checking Electrical Switches on Transmission
Note: If you have passed the ALDL Quick methods, the electrical switches are NOT causing the any lock-up condition. Go to test # 11.
SWITCH TYPE: Single terminal normally open
PART#: 8642473
TEST:
Connect one ohmmeter lead to the terminal of the switch and the other lead to the body of the switch. Ohmmeter should read infinite. Apply 60 psi of air to the switch and the ohmmeter should read 0.
SWITCH TYPE: Signal terminal normally closed
PART#: 8642569, 8634475
TEST:
Connect one ohmmeter lead to the terminal of the switch and the other lead to the body of the switch. Ohmmeter should read 0. Apply 60 psi of air to the switch and the ohmmeter should read infinite.
SWITCH TYPE: Two terminal normally open
PART#: 8643710
TEST:
Connect one ohmmeter lead to one terminal of the switch and the other lead to the other lead to the other terminal. Ohmmeter should read infinite. Apply 60 psi of air to the switch and the ohmmeter should read 0.
SWITCH TYPE: Two terminal normally closed
PART#: 8642346
TEST:
Connect one ohmmeter lead to one terminal of the switch and the other lead to the other terminal. Ohmmeter should read 0. Apply 60 psi of air to the switch and the ohmmeter should read infinite.
