Transmission Overview
Ford’s A4LD is the C-3 transmission, with an added 4th gear and converter clutch. This transmission appears two ways: with either a hydraulically- or an electrically-controlled 4th gear. We’ll look at both. The solenoids in these transmissions receive power whenever the key is on; the computer supplies ground to energize them.

Terminal Identification
Here’s a breakdown of the individual connector terminals on the unit that controls fourth gear hydraulically:

Shown from the terminal side of the transmission connector.

Here’s how to connect your signal monitor to check the transmission shift signals:

And here’s what your signal monitor should indicate: During most driving conditions, all of the lights should be off. But when the computer wants to engage the converter clutch, it supplies ground, which should turn the far left LED on.

Forcing Lockup Electrically
While all of the gears operate hydraulically, you can energize the TCC solenoid to apply the converter clutch. Start the engine, and put the unit in gear. Then give it gas until the transmission shifts into high gear.. Then complete the circuit to the TCC; you should feel the converter clutch apply.

Terminal Identification
Here’s a breakdown of the individual connector terminals on the unit that controls fourth gear electrically:

Checking the Shift Pattern
Here’s how to connect your signal monitor to check the signals for 4th gear and lockup:

And here’s what your signal monitor should indicate:

Forcing 3-4 and Lockup Electrically
While gears 1 through 3 operate hydraulically, you can energize overdrive and the TCC solenoid. Start the engine, and put the unit in gear. Give it gas until the transmission shifts into 3rd gear. Then complete the circuits as shown to shift the unit into 4th gear and to energize the TCC.

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