Chevrolet Silverado / GMC Sierra. Service manual — part 842

4. To remove the pressure control solenoid 1 (PCS1) or PCS2, remove three bolts (4) and the

pressure control valve retaining bracket (5). Remove accumulators (3) and springs (6) if
they do not fall out when the bracket (5) is removed.

5. Note the position of the solenoid connector and pull the solenoid (1) or (8) out of the bore

in the control valve assembly. The O-ring on the solenoid provides the resistance felt during
removal.

Installation Procedure

springs (6) which may fall from the bores. Be sure to
catch the accumulators and springs so as to prevent
damage to these parts.

The pressure control valve retaining bracket (5) must not
be modified. Note that the angle between the 2 bracket
surfaces is less than 90 degrees. Replace the bracket if
the angle is 90 degrees or more.

2008 Chevrolet Silverado 1500

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

Silverado

Fig. 15: Exploded View Of PCS1 and PCS2 Components
Courtesy of GENERAL MOTORS CORP.

1. Obtain the new solenoid (1) or (8). Lubricate new O-ring (2) or (7) with clean transmission

fluid. Install the O-ring and push the new solenoid into the control valve body bore with the
wiring harness connector in the correct position.

2008 Chevrolet Silverado 1500

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

Silverado

2. Install the 2 accumulators (3) and springs (6) before installing the pressure control valve

retaining bracket (5). The valve (3) goes in the bore first with the hollow end facing
outward, followed by the spring (6) which goes inside the hollow portion of the valve.

3. Install the pressure control valve retaining bracket (5), and install the 3 bolts (4).

Tighten: Tighten the bolts to 12 N.m (108 lb in).

Fig. 16: Reverse Signal Pipe Bolts
Courtesy of GENERAL MOTORS CORP.

4. Install the reverse signal pipe. Install the 2 bolts that fasten reverse signal pipe to the control

valve assembly.

NOTE:

Refer to Fastener Notice .

2008 Chevrolet Silverado 1500

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

Silverado

Tighten: Tighten the bolts to 12 N.m (108 lb in).

5. Reconnect the internal wiring harness to the solenoid.

6. Install the oil pan and transmission internal oil filter. Refer to Oil Pan Replacement.

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

OUTPUT FLANGE/YOKE REPLACEMENT

Removal Procedure

IMPORTANT: The FastLearn, adapt, procedure must be performed. This

can be done in 1 step using a scan tool. If this procedure is
not done, the TCM 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 will 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