Pontiac Fiero 1988 Service Manual page 760

HYDRAULIC DIAGNOSIS 125C-19
DR1¥E RANGE—FIRST GEAR
FORWARD
CLUTCH - APPLIED ROLLER CLUTCH -
HOLDlii
When the selector lever is moved to the Drive (D) position, the manual valve is repositioned to allow
line pressure to enter the Drive passage. Drive oil then flows to the following:
1. Forward Clutch
2. Governor Assembly
3. 1-2 Shift Valve
4. 1-2 Accumulator Valve
BASIC CONTROL
Drive oil is directed to the forward clutch through an orifice where it acts on the clutch piston to apply
the forward clutch.
Drive oil is directed to the 1-2 shift valve.
Drive oil is directed to the 1-2 accumulator valve and is regulated to a pressure called 1-2 accumulator
pressure; this pressure is directed to the 1-2 accumulator piston to act as a cushion for the band apply
on a 1-2 shift.
Drive oil at the governor assembly is regulated to another variable pressure called governor pressure.
Governor pressure increases with vehicle speed and acts against the 1-2 and 2-3 shift valves and
the 3-2 control valve.
SUMMARY
The converter is filled; the forward clutch is applied; the transmission is in Drive (D) Range — First Gear.
Figure 16 Drive Range - First Gear
JH0020-125C