Hummer H3. Manual — part 868

The pressure regulator valve regulates the oil pump output (line pressure) in response to the signal
fluid pressure, the spring force and the line pressure acting on the end of the valve. The line
pressure is routed through the valve and into both the converter feed and the decrease fluid
circuits. Regulated line pressure is also directed to the manual valve, the converter clutch valve,
the actuator feed limit valve and the regulated apply valve.

Pressure Relief Valve

Controlled by spring force, this checkball limits the maximum value of the line pressure. When
the line pressure reaches this limiting value, fluid is exhausted past the ball and returns to the
sump.

Line Pressure Tap

The line pressure tap provides a location to measure the line pressure with a fluid pressure gage.

Actuator Feed Limit Valve

Biased by spring force and orificed AFL fluid, it limits the maximum value of line pressure
entering the AFL fluid circuit. Below this limiting value, the AFL fluid pressure equals the line
pressure. The AFL fluid is routed to the pressure control solenoid valve, the 3-2 control solenoid
valve, the TCC PWM solenoid valve, the 1-2 and 2-3 shift solenoid valves and the 2-3 shift valve
train.

Pressure Control (PC) Solenoid Valve

Controlled by the powertrain control module (PCM), the PC solenoid valve regulates the filtered
AFL fluid into the torque signal fluid pressure. The PCM controls this regulation by varying the
current value to the PC solenoid valve in relation to the throttle position and other vehicle
operating conditions.

Torque Converter Clutch (TCC)

Torque Converter Clutch PWM Solenoid and Regulator Apply and Isolator Valve

AFL fluid is routed to the TCC PWM solenoid valve, in Park the PCM has the duty cycle turned
OFF. This prevents AFL fluid from entering the converter clutch signal fluid circuit. Regulated
line pressure is routed to the regulator apply valve, which is open with CC signal circuit empty
and blocks line pressure from entering the regulated apply circuit. Any fluid in the regulated
apply circuit will exhaust at the regulated apply valve.

TCC Solenoid Valve

2007 Hummer H3

2007 TRANSMISSION Automatic Transmission - 4L60-E/4L65-E/4L70-E - H3

Under normal operating conditions, the PCM keeps the normally open TCC solenoid valve de-
energized (OFF). Converter feed fluid exhausts through the open TCC solenoid valve and spring
force keeps the converter clutch apply valve in the release position.

Converter Clutch Valve

Held in the release position by spring force, it directs converter feed fluid into the release fluid
circuit. Also, fluid returning from the converter in the apply fluid circuit is routed through the
valve and into the cooler fluid circuit.

Torque Converter

Release fluid pressure unseats the TCC apply checkball (#9), keeps the pressure plate released
from the converter cover and fills the converter with fluid. Fluid exits the converter between the
converter hub and the stator shaft in the apply fluid circuit.

Cooler and Lubrication System

Cooler fluid from the converter clutch apply valve is routed through the transmission fluid cooler
and into the lubrication fluid circuits.

Manual Valve

Controlled by the selector lever and the manual shaft, the manual valve is in the Park (P) position
and directs the line pressure into the PR (Park/Reverse) fluid circuit. Line pressure is blocked
from entering any other fluid circuit at the manual valve.

Lo and Reverse Clutch Applies

Lo and Reverse Clutch Piston

The PR fluid seats the lo and reverse clutch checkball (#10) and is orificed to the outer area of
the piston. Orificing the PR fluid around the #10 checkball helps control the lo and reverse clutch
apply. Also, Lo/reverse fluid pressure from the lo overrun valve acts on the inner area of the lo
and reverse clutch piston in order to increase the clutch holding capacity.

Lo Overrun Valve

IMPORTANT: TCC converter feed valve assembly (#4), in the converter feed

circuit, prevents converter drain down. The orifice is smaller than
the exhaust through the TCC solenoid valve. Therefore, fluid
pressure does not build up at the end of the converter clutch
apply valve.

2007 Hummer H3

2007 TRANSMISSION Automatic Transmission - 4L60-E/4L65-E/4L70-E - H3

The PR fluid pressure moves the valve against the spring force and fills the Lo/reverse fluid
circuit. Lo/reverse fluid is orificed (323) back to the lo overrun valve in order to assist the PR
fluid in moving the valve against the spring force. The spring force provides a time delay for the
PR fluid filling the Lo/reverse fluid circuit. The Lo/reverse fluid is routed to the inner area of the
lo and reverse clutch piston in order to increase the holding capacity of the clutch.

Transmission Fluid Pressure (TFP) Manual Valve Position Switch Assembly

The TFP manual valve position switch consists of five fluid pressure switches: D2 and D3 are
normally closed and D4, Lo and Rev are normally open. All fluid circuits routed to the assembly
are empty and the TFP manual valve position switch signals the PCM that the transmission is in
either Park or Neutral.

Shift Solenoid Valves (1-2 and 2-3)

Both shift solenoid valves, which are normally open, are energized by the PCM and block fluid
from exhausting. This maintains the signal A fluid pressure at the 1-2 shift solenoid valve and
signal B fluid pressure at the 2-3 shift solenoid valve.

Shift Valves (1-2, 2-3 and 3-4)

Signal A fluid pressure holds the 1-2 shift valve in the downshift position and the 3-4 valve in the
upshift (first and fourth gear) position. The signal B fluid pressure from the 2-3 shift solenoid
valve holds the 2-3 shift valve train in the downshift position.

2007 Hummer H3

2007 TRANSMISSION Automatic Transmission - 4L60-E/4L65-E/4L70-E - H3

Fig. 486: Park - Engine Running Hydraulic Circuit Diagram
Courtesy of GENERAL MOTORS CORP.

REVERSE

When the gear selector lever is moved to the Reverse (R) position (from the Park position), the
following changes occur to the transmissions hydraulic and electrical systems:

Manual Valve

The manual valve moves to the Reverse position and line pressure enters the reverse fluid circuit.
As in Park, line pressure also fills the PR (Park/Reverse) fluid circuit. All other fluid circuits are
blocked by the manual valve.

Lo and Reverse Clutch

As in Park, PR fluid pressure acts on the outer area of the lo and reverse clutch piston to apply
the lo and reverse clutch. Also, Lo/reverse fluid from the lo overrun valve acts on the inner area
of the piston to increase the holding capacity of the clutch (see Note below).

Reverse Input Checkball (#3)

Reverse fluid pressure seats the #3 checkball, flows through orifice #17 and fills the reverse input

2007 Hummer H3

2007 TRANSMISSION Automatic Transmission - 4L60-E/4L65-E/4L70-E - H3