Air Pressure Tests
| Item | Part Number | Description |
|---|---|---|
| 1 | - | Servo release |
| 2 | - | Servo apply |
| 3 | - | Direct clutch apply |
| 4 | - | Reverse clutch apply |
| 5 | - | Torque converter bypass |
| 6 | - | Low/reverse clutch |
| 7 | - | Torque converter charge |
| 8 | - | Forward clutch apply |
| 9 | - | Servo accumulator apply |
| 10 | - | Forward servo accumulator apply |
A no-drive condition can exist even with correct transmission fluid pressure because of inoperative clutches or bands. An erratic shift can be located through a series of checks by substituting air pressure for transmission fluid pressure to determine the location of the failure.
Follow the procedure to determine the location of the inoperative clutch or band by introducing air pressure into the various test plate passages.
Apply air to the appropriate passage(s). A dull thud should be felt or heard or movement could be observed when the component applies. There should be no hissing sound when the component is fully applied.
- Drain transmission fluid and remove the transmission fluid pan.
- Remove the main control valve body.
- Install the transmission test plate and gasket. Use the transmission fluid pan bolts to hold the test plate down. Tighten the bolts to 10 N.m (89 lb-in).
- Apply air to the appropriate clutch port (refer to the diagram). A dull thud may be heard or movement felt when the component is applied or released. If clutch seals or check balls are leaking, a hissing sound may be heard.
If test results indicate that the servos do not operate, disassemble, clean and inspect them to locate the source of the concern.
If air pressure applied to the clutch passages fails to operate a clutch, or operates another clutch simultaneously, disassemble and use air pressure to check the transmission fluid passages in the center support and clutches to detect obstructions.