Hummer H2. Manual - part 2362

Fig. 466: Overdrive Range, First Gear 
Courtesy of GENERAL MOTORS CORP.

 

2004 Hummer H2 

2004 TRANSMISSION Automatic Transmission - 4L60-E/4L65-E (Introduction) - Hummer H2

  

OVERDRIVE RANGE, SECOND GEAR

As vehicle speed increases and other operating conditions are appropriate, the PCM de-energizes the 1-2 shift 
solenoid valve in order to shift the transmission to second gear. 

1-2 Shift Solenoid (SS) Valve 

De-energized (turned OFF) by the PCM, the normally open solenoid opens and signal A fluid exhausts through 
the solenoid. 

2-3 Shift Solenoid (SS) Valve 

Energized (ON) as in first gear, the 2-3 shift solenoid valve blocks signal B fluid from exhausting through the 
solenoid. This maintains signal B fluid pressure at the solenoid end of the 2-3 shift valve. 

1-2 Shift Valve 

Without signal A fluid pressure, spring force moves the valve into the upshift position. D4 fluid is routed 
through the valve and fills the 2nd fluid circuit. 

1-2 Shift Checkball (#8) 

The 2nd fluid pressure seats the #8 checkball, flows through orifice #16, and fills the 2nd clutch fluid circuit. 
This orifice helps control the 2-4 band apply rate. 

2-4 Servo Assembly 

The 2nd clutch fluid pressure moves the #8 checkball, flows through orifice #16 and fills the 2nd clutch fluid 
circuit. This orifice helps to control the 2-4 band apply rate. 

1-2 Accumulator 

The 2nd clutch fluid pressure also moves the 1-2 accumulator piston against the spring force and the 
accumulator fluid pressure. This action absorbs the initial 2nd clutch fluid pressure in order to cushion the 2-4 
band apply rate. Also, the movement of the 1-2 accumulator piston forces some accumulator fluid out of the 
accumulator assembly. This accumulator fluid is routed back to the accumulator valve. 

Accumulator Valve 

The accumulator fluid forced out of the 1-2 accumulator is orificed (#30) to the end of the accumulator valve. 
This pressure moves the valve against the spring force and the torque signal fluid pressure in order to regulate 
the exhaust of excess accumulator fluid. This regulation provides additional control for the 2-4 band apply rate. 

IMPORTANT: The actuator feed limit (AFL) fluid continues to feed the signal A fluid circuit 

through orifice #25. However, the exhaust port through the solenoid is larger 
than orifice #25 in order to prevent a pressure buildup in the signal A fluid 
circuit. Exhausting signal A fluid is represented by the blue arrows.

 

2004 Hummer H2 

2004 TRANSMISSION Automatic Transmission - 4L60-E/4L65-E (Introduction) - Hummer H2

  

The fluid circuit shows the exhaust of the accumulator fluid during the shift by the arrow directions in the 
accumulator fluid circuit. 

2-3 Shift Valve Train 

The signal B fluid pressure from the 2-3 shift solenoid valve holds the valve train in the downshift position. The 
2nd fluid is routed through the 2-3 shuttle valve and fills the servo feed fluid circuit. 

3-4 Relay Valve and 4-3 Sequence Valve 

Spring force holds these valves in the downshift position (first, second and third gear positions). The 2nd fluid 
is blocked by the 3-4 relay valve and the servo feed fluid is blocked by both valves in preparation for a 3-4 
upshift. 

3-2 Downshift Valve 

Spring force holds the valve closed, blocking the 2nd fluid and the 2nd clutch fluid. This valve is used in order 
to help control the 3-2 downshift. 

3-2 Control Solenoid Valve 

In second gear, the PCM energizes the normally closed solenoid. This opens the AFL fluid circuit to fill the 3-2 
signal fluid circuit. 

3-2 Control Valve 

The 3-2 signal fluid pressure moves the valve against the spring force. This action does not affect the 
transmission operation in second gear. 

3-4 Shift Valve 

Signal A fluid pressure exhausts and spring force moves the valve into the downshift position (second and third 
gear positions). 

Torque Converter Clutch 

TCC Solenoid Valve 

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

 

2004 Hummer H2 

2004 TRANSMISSION Automatic Transmission - 4L60-E/4L65-E (Introduction) - Hummer H2

  

Fig. 467: Overdrive Range, Second Gear 
Courtesy of GENERAL MOTORS CORP.

 

2004 Hummer H2 

2004 TRANSMISSION Automatic Transmission - 4L60-E/4L65-E (Introduction) - Hummer H2