Pontiac Fiero 1988 Service Manual page 766

HYDRAULIC DIAGNOSIS 125C-25
DRIVE
RANGE—THIRD GEAR
CONVERTER CLUTCH - APPLIED FORWARD CLUTCH - APPLIED DIRECT CLUTCH - APPLIED
BASIC CONTROL
When car speed in Drive Range 3rd Gear, reaches converter clutch engagement speed, the C3 or gover-
nor pressure switch (depending on system) will activate the solenoid, closing the exhaust valve. This
allows solenoid circuit oil t o move the converter clutch control valve against line pressure. With the
converter clutch control valve in the apply position, regulated line oil, from the converter clutch regulator
valve, is allowed t o pass into the converter apply passage. It then flows through the turbine shaft t o
the apply side of the converter clutch. The regulated line oil, from the converter clutch regulator valve,
controls the apply feel of the pressure plate.
As the pressure plate begins to move to its applied position, release oil on the front side of the pressure
plate is redirected back between the turbine shaft and pump drive shaft and exhausted at t h e
converter clutch control valve through an orifice, to time the clutch apply. When the converter clutch
control valve moved to the apply position, orificed converter feed oil entered the converter to cooler
passage to provide oil to the lubrication system.
SUMMARY
The forward and direct clutches are applied, the converter clutch is applied and the intermediate band
is released; the transmission is in Drive (D) Range — Third Gear (direct drive).
Figure 22 Drive Range - Third Gear - Converter Clutch Applied