Chevrolet Silverado / GMC Sierra. Service manual — part 733

TOOLS REQUIRED

DT-47825 Control Solenoid Test Plate. See Special Tools.

The purpose of this procedure is to test the operation of the control solenoid (w/body and TCM)
valve assembly for a stuck open or stuck closed solenoid. The DT-47825 bolts to the mounting
surface of the control solenoid (w/body and TCM) valve assembly. See Special Tools.
Compressed air is attached to the test block, through the control solenoid (w/body and TCM)
valve assembly solenoid passage and back to a pressure gage on the test plate, sent through the
control solenoid (w/body and TCM) valve assembly solenoid, and back to the test plate pressure
port.

An air pressure gage is used to display the air passing through the solenoid. If the solenoid is
unable to allow air through or the air is constantly flowing through the solenoid may be stuck.
The scan tool is used to command the solenoids On and Off while watching the air pressure test
gage to determine if the solenoid is functioning correctly. The recommended shop air pressure for
this test is 620.5-689.4 Kpa (90-100 psi).

2008 Chevrolet Silverado 1500

2008 TRANSMISSION Automatic Transmission - 6L50/6L80/6L90 - Cab & Chassis Sierra, Cab & Chassis Silverado,

Sierra & Silverado

Fig. 3: Control Solenoid (w/Body and TCM) Valve Assembly with Control Solenoid Test
Plate
Courtesy of GENERAL MOTORS CORP.

Callout

Component Name

1

Filter Plate Assembly

2

Control Solenoid Valve Assembly

3

DT-47825 Control Solenoid Test Plate

2008 Chevrolet Silverado 1500

2008 TRANSMISSION Automatic Transmission - 6L50/6L80/6L90 - Cab & Chassis Sierra, Cab & Chassis Silverado,

Sierra & Silverado

The TCM will normally cycle some of the transmission solenoids On and Off to keep the solenoid
passages clean and clear, This is a normal function and will cause the valves to cycle open and
closed quickly when the TCM is powered up. This will make the pressure gage needle flicker or
move from high and low as the valves open and close, allowing air to exit the ports where the
pressure gage is not connected.

It is necessary to drain the control solenoid (w/body and TCM) valve assembly of all remaining
transmission fluid before attaching the test plate. Use caution when attaching air to the test plate,
as any remaining transmission fluid in the control solenoid (w/body and TCM) valve assembly
will be forced out. Use shop towels to cover the test plate ports in order to prevent fluid from
being released into the air.

Preliminary Procedures

1. Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle .

2. Remove the transmission fluid pan and filter. Refer to Automatic Transmission Fluid,

Fluid Pan and/or Filter Replacement.

3. Remove the transmission electrical connector. Refer to Automatic Transmission

Electrical Connector Passage Sleeve Replacement.

4. Remove the control solenoid (w/body and TCM) valve assembly from the transmission.

Refer to Control Valve Lower Body and Upper Body Replacement.

4

Air Connection Port

5

Transmission 16-Way Pass-Through Connector

6

Electrical Connector Slide Lock

IMPORTANT: To avoid solenoid overheating and possible internal damage, do

not continuously operate the solenoid for more than 2 minutes at
a time.

2008 Chevrolet Silverado 1500

2008 TRANSMISSION Automatic Transmission - 6L50/6L80/6L90 - Cab & Chassis Sierra, Cab & Chassis Silverado,

Sierra & Silverado

Fig. 4: Solenoid Testing Procedure
Courtesy of GENERAL MOTORS CORP.

1. Align and install the electrical connector sleeve to the control solenoid (w/body and TCM)

valve assembly and secure with the connector slide lock.

Callout

Component Name

1

Regulated Air Supply

2

Test Ports

3

Scan Tool

4

Test Pressure Gage

5

Electrical Connector Sleeve

NOTE:

The TCM connector sleeve allows the test tool harness to be
correctly orientated for electrical operation of the TCM. Do not
connect the test harness to the TCM without using the
connector sleeve. Failure to use the sleeve could allow the test
harness to be incorrectly positioned which will result in
permanent TCM damage.

2008 Chevrolet Silverado 1500

2008 TRANSMISSION Automatic Transmission - 6L50/6L80/6L90 - Cab & Chassis Sierra, Cab & Chassis Silverado,

Sierra & Silverado