Express 1500 AWD V8-5.3L (2008)
2. Pre-assemble the following parts:
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The reverse boost valve bushing
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A new reverse boost valve
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A new pressure regulator spring retainer
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The added isolator pressure regulator spring
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The pressure regulator spring
3. Install the pre-assembled parts into the pump bore.
4. Install the reverse boost valve bushing retainer ring while holding the reverse boost valve bushing in place.
Ensure the retainer ring (2) is in the groove.
5. Install the transmission oil pan and the oil filter. Refer to Automatic Transmission Fluid and Filter Replacement (See: Service and
Repair/Removal and Replacement) .
6. Lower the vehicle.
7. Fill the transmission to the proper level with DEXRON(R) VI transmission fluid. Refer to Transmission Fluid Check (See: Testing and
Inspection/Component Tests and General Diagnostics/4L80-E/4L85-E - Automatic Transmission/Transmission Fluid Checking) .
Important: It is recommended that transmission adaptive pressure (TAP) information be reset.
Resetting the TAP values using a scan tool will erase all learned values in all cells. As a result, The ECM, PCM or TCM will need to
relearn TAP values. Transmission performance may be affected as new TAP values are learned.
8. Reset the TAP values. Refer to Transmission Adaptive Functions (See: Description and Operation/4L80-E/4L85-E - Automatic
Transmission/Transmission Adaptive Functions) .
