Chevrolet Silverado / GMC Sierra. Service manual — part 845

8. Perform the FastLearn procedure. Refer to FastLearn Procedure.

PRESSURE SWITCH MANIFOLD REPLACEMENT

Removal Procedure

IMPORTANT: The FastLearn (adapt) procedure must be performed. This

can be done in one step using a scan tool. If this procedure is
not done, the TCM's adaptive values will be at the settings
that it learned for the old components. and will be in slow
adaptive mode. Under these conditions, it would take an
unacceptably long time for the adaptive values to converge
to levels suitable for the new transmission.

2008 Chevrolet Silverado 1500

2008 TRANSMISSION Automatic Transmission - Allison - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra &

Silverado

Fig. 23: TFP Switch
Courtesy of GENERAL MOTORS CORP.

IMPORTANT: Individual pressure switches cannot be replaced. When any

pressure switch needs replacing, the entire assembly must
be replaced.

2008 Chevrolet Silverado 1500

2008 TRANSMISSION Automatic Transmission - Allison - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra &

Silverado

1. Remove the oil pan and transmission internal oil filter. Refer to Oil Pan Replacement.

2. Disconnect the internal wiring harness connector from the transmission fluid pressure (TFP)

switch (2).

3. Remove six bolts (1). Remove the TFP switch (2).

Installation Procedure

IMPORTANT: The modulated main pressure (MAIN MOD) solenoid has been

removed for clarity.

CAUTION: Refer to BATTERY DISCONNECT CAUTION .

2008 Chevrolet Silverado 1500

2008 TRANSMISSION Automatic Transmission - Allison - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra &

Silverado

Fig. 24: TFP Switch
Courtesy of GENERAL MOTORS CORP.

1. Place the new TFP manifold assembly (2) in position and install one bolt (1) in a recessed

NOTE:

Refer to Fastener Notice .

2008 Chevrolet Silverado 1500

2008 TRANSMISSION Automatic Transmission - Allison - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra &

Silverado