Air Pressure Tests

WARNING: This page is about a different car, the 2009 Ford Mustang. However, it is still accessible from the selected car via links, so may be relevant.

Fig 1: Identifying Air Pressure Testing Ports

Courtesy of FORD MOTOR CO.

Item	Part Number	Description
1	-	Reverse servo
2	-	Intermediate servo
3	-	Overdrive servo
4	-	Coast clutch
5	-	Forward clutch
6	-	Direct clutch
7	-	Reverse servo modulator

A no-drive or erratic shift condition may be due to inoperative bands and clutches. To diagnose these conditions, a series of checks can be made by substituting air pressure for fluid to determine the location of the damaged or obstructed component.

Follow the procedure to determine the location of the inoperative clutch or band by substituting air pressure into the various test plate passages.

NOTE: Use only dry, regulated 276 kPa (40 psi) maximum air pressure.

Remove the main control valve body. Refer to Main Control Valve Body .
Install the transmission test plate and gasket. Tighten to 10 N.m (89 lb-in).

NOTE: Do not apply air to the test plate vent hole.

Apply air to the appropriate clutch or servo port (refer to plate layout diagram). Refer to the Air Pressure Test Diagnostic Chart for conditions, possible causes and actions.
After the testing is completed, remove the air test plate and gasket and proceed with any repairs that are needed.
After the repairs are completed, install the main control valve body. Refer to Main Control Valve Body .

AIR PRESSURE TEST DIAGNOSTIC CHART

Condition	Possible Causes	Actions
Dull thud heard or movement felt when air is applied and released	Clutches, bands and fluid passages are OK.	Concerns may not be in the transmission. Check the PCM, wiring harness and non-transmission related components.
No drive	Clutches and bands inoperative.	Disassemble the transmission, clean and inspect to locate area of concern.
Erratic shifts	Clutches and bands inoperative due to incorrect pressures.	Disassemble the transmission, clean and inspect to locate area of concern.
No dull thud heard	Clutches, bands and fluid passages may be damaged or obstructed.	Disassemble the transmission, clean and inspect to locate area of concern.
No movement felt	Clutches, bands and fluid passages may be damaged or obstructed.	Disassemble the transmission, clean and inspect to locate area of concern.
Hissing sound heard	Clutch seals or check ball may be damaged or leaking.	Disassemble the transmission, clean and inspect to locate area of concern.
Servos do not operate	Seals and pistons may be damaged. Supply and release ports may be obstructed. Spring may be broken.	Disassemble the transmission, clean and inspect to locate area of concern.
Multiple clutches are applied	Fluid passages in the center support or the clutch cylinders may be obstructed.	Disassemble the transmission, clean and inspect to locate area of concern. Check fluid passages in the center support for obstructions.