This comprehensive service and repair manual provides detailed instructions and technical information for the 6L80 and 6L90 automatic transmissions, covering models from 2006 to 2014. The manual is designed to be user-friendly for both experienced mechanics and DIY enthusiasts, offering clear and concise text alongside high-quality diagrams and illustrations.

The manual covers a wide range of topics, including:

- **Introduction:** Providing an overview of the 6L80 and 6L90 transmissions.
- **Torque Converter:** Detailed information on the torque converter's function, maintenance, and troubleshooting.
- **Lubrication Points:** Identifying and explaining the importance of lubrication points for optimal performance and longevity.
- **Seal Locations:** Providing a comprehensive guide to seal locations, making it easier to identify and replace seals when necessary.
- **Troubleshooting:** Offering guidance on diagnosing and resolving common transmission issues.
- **Trouble Codes:** Explaining transmission trouble codes and how to interpret them.
- **Special Tools:** Identifying the specialized tools required for servicing these transmissions.
- **Assembly:** Step-by-step instructions for assembling the transmission after repair or maintenance.
- **Disassembly:** Detailed procedures for disassembling the transmission, allowing for thorough inspection and repair.
- **Upgrading Pistons:** Guidance on upgrading pistons for improved performance and reliability.
- **Solenoid Resistance Chart:** A detailed chart listing the resistance values for solenoids, aiding in diagnosing electrical issues.
- **Check Ball Locations:** Identification and explanation of check ball locations for proper transmission operation.
- **Shift Speed Chart:** A chart illustrating the expected shift speeds for different gears and conditions.
- **Line Pressure:** Information on line pressure specifications and troubleshooting techniques.
- **Input Drum:** Detailed information on the input drum's function, maintenance, and repair.
- **Reverse Drum:** A comprehensive guide to the reverse drum's operation, maintenance, and troubleshooting.
- **Gear Train:** A detailed explanation of the transmission's gear train, including components and operation.
- **Unit Assembly:** Detailed instructions for assembling the transmission components.
- **Wiring Schematic:** A clear schematic of the transmission's electrical system.
- **Clutch Assembly:** Step-by-step instructions for assembling and adjusting clutches.
- **Overrun Clutch:** Information on the overrun clutch's function and maintenance.
- **Forward Clutch:** Detailed information on the forward clutch, including operation and repair.
- **Valve Body:** Comprehensive guidance on the valve body's operation, troubleshooting, and repair.
- **Case Preparation:** Instructions for preparing the transmission case for reassembly.

This manual provides everything you need to confidently perform service and repair on your 6L80 or 6L90 transmission, saving you time and money.

The 6L80 and 6L90 are six-speed automatic transmissions developed by General Motors and used in a wide variety of vehicles produced by their brands, including Cadillac, Chevrolet, Holden, Pontiac, GMC, and Hummer. These transmissions are electronically controlled and feature a sophisticated hydraulic system, allowing for smooth and efficient gear changes across a wide range of driving conditions. The 6L80, designed for rear-wheel-drive applications, can handle up to 450 lb-ft of torque, while the 6L90, optimized for front-wheel-drive vehicles, boasts a higher torque capacity of 560 lb-ft. Both transmissions utilize a planetary gearset with multiple clutches and brakes, enabling multiple gear ratios to maximize performance and fuel efficiency.

The 6L80 and 6L90 transmissions are known for their durability and reliability, contributing to their widespread adoption across numerous vehicle models. They are equipped with several advanced features designed to enhance performance and drivability, including electronic throttle control, adaptive shift scheduling, and a lock-up torque converter. The transmissions are also equipped with various sensors that monitor fluid temperature, pressure, and speed, helping to ensure smooth operation and prevent potential issues. However, as with any complex mechanical system, regular maintenance is crucial to optimize the transmission's performance and extend its lifespan. The "6L80 6L90 Automatic Gearbox Full Service Repair Manual" provides comprehensive guidance on proper service procedures, troubleshooting, and repair techniques for these transmissions, empowering users to maintain their vehicles effectively.