This comprehensive workshop and parts manual provides detailed information for repairing and rebuilding the 6L80 and 6L90 automatic transmissions. It is designed to be a valuable resource for both experienced mechanics and DIY enthusiasts. The manual covers a wide range of topics, including:

* **Introduction**: A general overview of the 6L80 and 6L90 transmissions, their features, and operating principles.
* **Torque Converter**: In-depth instructions on troubleshooting, dismantling, inspecting, and reassembling the torque converter.
* **Lubrication Points**: Detailed diagrams and explanations of all lubrication points within the transmission.
* **Seal Locations**: Clear illustrations and descriptions of all seal locations and their proper installation techniques.
* **Troubleshooting**: A systematic approach to diagnosing transmission problems, including common symptoms, causes, and solutions.
* **Trouble Codes**: A comprehensive list of diagnostic trouble codes (DTCs) for the 6L80 and 6L90 transmissions, with their meanings and corresponding troubleshooting steps.
* **Special Tools**: Specifications and instructions for using special tools required for specific repair and maintenance procedures.
* **Assembly**: Step-by-step instructions on assembling the transmission, with detailed illustrations and explanations of each component's function.
* **Disassembly**: Clear and concise instructions on dismantling the transmission, ensuring proper disassembly procedures to avoid damage.
* **Upgrading Pistons**: Guidance on upgrading transmission pistons for improved performance and reliability.
* **Solenoid Resistance Chart**: A detailed chart providing solenoid resistance values for diagnostic and troubleshooting purposes.
* **Check Ball Locations**: Diagrams and explanations of the location and function of check balls within the transmission.
* **Shift Speed Chart**: A chart displaying the recommended shift speeds for different gears and operating conditions.
* **Line Pressure**: Information on line pressure specifications, troubleshooting low or high pressure, and adjustment procedures.
* **Input Drum**: Detailed instructions on inspecting, repairing, and replacing the input drum.
* **Reverse Drum**: Comprehensive information on the reverse drum, including inspection, repair, and replacement procedures.
* **Gear Train**: Detailed diagrams and explanations of the gear train, including function, assembly, and troubleshooting.
* **Unit Assembly**: Step-by-step instructions on assembling the transmission unit, including all components and their proper alignment.
* **Wiring Schematic**: A complete wiring diagram of the transmission control system, covering all solenoids, sensors, and connections.
* **Clutch Assembly**: Detailed information on the different clutch packs within the transmission, including assembly, disassembly, and troubleshooting.
* **Overrun Clutch**: Instructions on inspecting, repairing, and replacing the overrun clutch.
* **Forward Clutch**: Comprehensive information on the forward clutch, including assembly, disassembly, and troubleshooting.
* **Valve Body**: Detailed diagrams and explanations of the valve body, including function, troubleshooting, and repair procedures.
* **Case Preparation**: Instructions on properly preparing the transmission case for reassembly, ensuring a clean and leak-free unit.

This workshop and parts manual empowers you with the knowledge and instructions needed to successfully repair and rebuild the 6L80 and 6L90 automatic transmissions.

The 6L80 and 6L90 are six-speed automatic transmissions designed and manufactured by General Motors for use in a wide range of vehicles, including cars, trucks, and SUVs. These robust transmissions are known for their high torque capacity and smooth shifting, making them ideal for performance and heavy-duty applications. The 6L80 is typically found in rear-wheel drive vehicles and has a maximum torque capacity of 450 lb-ft, while the 6L90, engineered for larger vehicles, can handle up to 600 lb-ft of torque. They are equipped with electronic control systems that adapt to different driving conditions, providing optimal performance and fuel efficiency.

The 6L80 and 6L90 transmissions have found a place in a vast array of General Motors vehicles, from luxury performance models like the Cadillac XLR-V, Corvette, CTS-V, STS-V, and Escalade to powerful trucks like the Chevrolet Silverado and GMC Yukon Denali. The transmissions are also utilized in muscle cars like the Chevrolet Camaro and Pontiac G8, as well as Holden Commodore models produced in Australia featuring the impressive VE and VF iterations, including the Statesman/Caprice. Even the rugged Hummer H2 benefitted from the capabilities of the 6L80 transmission. This widespread adoption signifies the versatility and reliability of these transmissions, offering a combination of power handling, efficiency, and durability that caters to a diverse range of automotive needs.