GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2004 🢒 GMC C Sierra - 2WD 🢒 Transmission/Transaxle 🢒 Automatic Transmission - Allison 🢒 Automatic Transmission Electronic Component Views
Figure 1:

Transmission Control Module (M74)
Object Number: 769662 Size: MF
(1)Transmission Control Module Connectors
(2)Transmission Control Module
(3)Powertrain Control Module (PCM) (Gas) / Engine Control Module (ECM) (Diesel)
Figure 2:

Engine Harness to Transmission-Allison
Object Number: 769664 Size: MF
(1)Turbine Sensor Harness Connector
(2)Power Take-Off (PTO) Connector
(3)Output Speed Sensor Harness Connector
(4)Transfer Case Selector Shift Control Switch
(5)Transmission Connector Harness
(6)Park/Neutral Position (PNP) Switch Connectors
(7)Allison Transmission
(8)Engine Harness
(9)Automatic Transmission Input Shaft Speed (ISS) Sensor
Figure 1:

Transmission Control Module (M74)
Object Number: 769662 Size: MF
(1)Transmission Control Module Connectors
(2)Transmission Control Module
(3)Powertrain Control Module (PCM) (Gas) / Engine Control Module (ECM) (Diesel)
Figure 2:

Engine Harness to Transmission-Allison
Object Number: 1458146 Size: LF
(1)Automatic Transmission Input Shaft Speed (ISS) Sensor
(2)Turbine Sensor Harness Connector
(3)Power Take-Off (PTO) Connector
(4)Output Speed Sensor Harness Connector
(5)Transfer Case Selector Shift Control Switch
(6)Transmission Connector Harness
(7)Park/Neutral Position (PNP) Switch
(8)Allison Transmission
(9)Engine Harness
Figure 3:

Tow/Haul Switch Location
Object Number: 1327928 Size: MF
(1)Tow/Haul Switch