Air Pressure Tests

Special Testing Procedures

Air Pressure Test









A no-drive condition can exist even with correct transmission fluid pressure because of inoperative clutches. Refer to the Clutch Application Chart to determine which clutch is applied in each gear range. A clutch concern can be located through a series of checks by substituting air pressure for fluid pressure to determine the location of the concern.

Example: When the selector lever is in a forward gear range, a no-drive condition may be caused by an inoperative forward clutch.

1. Drain the transmission fluid. Remove the transmission fluid pan.

2. Remove the transmission fluid filter and seal assembly along with the main control.

3. The inoperative clutches can be located by applying air pressure into the appropriate clutch port.

4. Apply air pressure to the appropriate clutch port. A dull thud may be heard or movement felt when a clutch piston is applied. If the clutch seals or check ball are leaking, a hissing sound may be heard.

5. If the clutches fail to operate during the air check:
- the piston seals are not seated, damaged or installed incorrectly.

- plugged feed holes for clutch apply in the case and/or clutch cylinder.

- damaged piston and/or clutch cylinder.

- damaged or missing shaft seals in clutch circuit

6. Service as required and recheck.