Direct Clutch Pressure Test--(AOD)

DIRECT CLUTCH PRESSURE TEST-AOD)

The direct clutch pressure test outlined below will diagnose a low pressure condition or leakage in the direct clutch circuit. A difference of 15 psi or more between direct clutch pressure and line pressure (read at the forward clutch pressure tap) will prevent a 3-4 shift.






1. Attach 0-300 psi pressure gages to the forward clutch pressure tap and to the direct clutch pressure tap (Fig. 9). Gauge accuracy must be capable of distinguishing a 15 psi difference. (If this test is done in conjunction with a control pressure test, pressure gages will be attached to all pressure taps.) Have sufficient flexible hose to read the gages in the vehicle.

CAUTION:Pressure gauges affect the shift quality of the transmission. Care should be taken not to accelerate or decelerate rapidly. Possible transmission failure could result.

2. Drive the vehicle. When pressure is applied to the direct clutch, note the difference between the line pressure read at forward clutch pressure tap and the direct clutch pressure.
3. If the difference in pressures is less than 15 psi, the direct clutch circuit is Ok.
4. If the difference is greater than 15 psi, there could be a leak in the direct clutch pressure circuit. If the difference does exceed 15 psi, the gauges on line pressure and direct clutch pressure can be switched to confirm that gage calibration difference is not the cause.