Air Pressure Tests

Air Pressure Tests
A no-drive condition can exist even with correct transmission fluid pressure because of inoperative clutches or bands. Refer to the Band and Clutch Application Charts A and B to determine the appropriate elements. A clutch concern can be located by substituting air pressure for oil pressure to determine the location of the malfunction.
For example, when the transaxle range selector lever is in a forward gear range ((D), 2, 1), a no-drive condition can be caused by an inoperative forward clutch.

Test Procedures
Carry out the following procedures:
1. Drain the transaxle. Remove main control cover.
2. Remove the main control as an assembly with the solenoid body assembly.
3. The inoperative clutches can be located by applying air pressure into the appropriate clutch port. Refer to Air Pressure Test Port Locations diagram.
4. Install the transmission test plate using 6 bolts.
^ Tighten to 12 Nm (9 ft. lbs.).

5. CAUTION: The coast clutch circuit should not be applied unless air pressure is maintained in the forward clutch circuit. Failure to do so can result in the coast clutch piston coming out of the forward clutch piston.

NOTE: Refer to the Band and Clutch Application Charts A and B.

Apply air pressure 275 kPa (40 psi) to the appropriate clutch port (refer to Air Pressure Test Port Locations diagram). A dull thud may be heard, or movement felt when the clutch piston is applied. If clutch seals or check balls are leaking, a hissing may be heard.

Air Pressure Test Port Locations:

Air Pressure Test Results
If 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 clutches simultaneously, inspect the fluid passages in the case.

If air pressure applied to the accumulator fails to operate an accumulator, remove and inspect case passages and piston.