Pontiac Fiero 1988 Service Manual page 762

HYDRAULIC DIAGNOSIS 125C-21
DRIVE R A N G E — S E C O N D GEAR
FORWARD CLUTCH - APPLIED
INTERMEDIATE BAND - APPLIED
As both vehicle speed and governor pressure increase, the force of governor oil acting on the 1-2 shift
valve overcomes the pressure of shift T.V. oil and the force of the 1-2 T.V. spring. This allows the 1-2
valve to open and drive oil to enter the second (2nd) oil passage. This oil is called second (2nd) oil.
Second oil from the 1-2 shift valve is directed to the following:
1. Intermediate Servo
2. 1-2 Accumulator Piston
BASIC CONTROL
Second oil from the 1-2 shift valve is directed to the intermediate servo to apply the intermediate band.
At the same time, 2nd oil moves the 1-2 accumulator piston against 1-2 accumulator pressure and
the accumulator spring to maintain a controlled build-up of pressure on the intermediate servo during
the 1-2
shift for a smooth band apply.
SUMMARY
The forward clutch and the intermediate band are applied; the transmission is in Drive (D) Range —
Second Gear.
JH0021-125C
Figure 18 Drive Range - Second Gear