Pontiac Fiero 1988 Service Manual page 758

HYDRAULIC DIAGNOSIS 125C-17
NEUTRAL— ENGINE RUNNING
DIRECT CLUTCH - RELEASED
F O R W A R D CLUTCH - RELEASED LO AND REVERSE CLUTCH - RELEASED
CONVERTER CLUTCH - RELEASED
INTERMEDIATE BAND - RELEASED ROLLER CLUTCH - NOT HOLDING
When the selector lever is moved t o the Neutral (N) position, the manual valve is positioned to allow
line pressure to enter t w o (2) passages as follows:
FIRST: It enters the Reverse, Neutral, Drive, Intermediate (RNDI) passage. RNDI oil is directed to t h e
seat RNDI and detent check ball (6), and to the throttle valve where it is regulated to a variable pressure
called throttle valve (T.V.) pressure. T.V. pressure increases w i t h carburetor opening and is directed
to the shift throttle valve. This valve limits shift T.V. oil pressure from going above 6 2 0 kPa (90 psi).
Shift T.V. oil is then directed to the 1-2 and 2-3 throttle valves, T.V. boost valve, T.V. plunger and the
1-2 accumulator valve.
Shift T.V. oil acting on t h e T.V. boost valve will boost line pressure according to throttle opening.
SECOND: Line pressure enters t h e Reverse, Neutral, Drive (RND) passage and is directed to a land
on t h e 2-3 shift valve.
The converter is filled; all the clutches and the band are released; the transmission is in Neutral (N).
SUMMARY
J H 0 0 1 9 - 1 2 5 C
Figure 14 Neutral - Engine Running