This section provides the following information:
• General diagnosis information on transmissions
• Procedures for diagnosing the Hydra-matic transmission
When you diagnose any condition of the Hydra-matic transmission, begin with A Diagnostic Starting Point. This procedure indicates the proper path of diagnosing the transmission by describing the basic checks. This procedure will then refer you to the locations of specific checks. After you have determined the cause of a condition, refer to REPAIR INSTRUCTIONS - Off Vehicle for repair procedures. If the faulty component is not serviceable without removing the transmission from the vehicle, refer to REPAIR INSTRUCTIONS - On Vehicle for repair information.
NOTE: Do not, under any circumstances, attempt to diagnose a powertrain
condition without basic knowledge of this powertrain. If you perform diagnostic procedures without this basic knowledge, you may incorrectly diagnose the condition or damage the powertrain components.
You must be familiar with some basic electronics in order to use this section of the service manual. You should also be able to use the following special tools:
• A digital multimeter (DMM)
• A circuit tester
• Jumper wires or leads
• A line pressure gage set
NOTE: If you probe a wire with a sharp instrument and do not properly seal
the wire afterward, the wire corrodes and an open circuit results.
Diagnostic test probes are now available that allow you to probe individual wires without leaving the wire open to the environment. These probe devices are inexpensive and easy to install and they permanently seal the wire from corrosion.