Air Pressure Test
A no-drive condition can exist, even with correct transmission fluid pressure, because of inoperative clutches or bands. Refer to the Band/Clutch Application Chart to determine the appropriate elements. 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 transmission range selector lever is in a forward gear range ((D), 2, 1), a no-drive condition may be caused by an inoperative forward clutch.
- Drain the transmission fluid. Remove the transmission fluid pan.
- Remove the filter and seal assembly, the solenoid body, the control assemblies and separator plate, upper/lower gaskets.
- The inoperative clutches can be located by applying air pressure into the appropriate clutch port. See the Air Pressure Test Port Locations illustration for clutch port locations.
- Apply air pressure to the appropriate clutch port (see diagram). 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 may be heard.
- If the clutches fail to operate during the air check:
- the piston seals are not seated, damaged, not installed.
- plugged feed holes for clutch apply in the case and/or clutch cylinder.
- damaged piston and/or clutch cylinder.
- Service as required and recheck.