The 4L60 is a widely used four-speed automatic transmission found in various General Motors (GM) vehicles. It was introduced in 1990 as a replacement for the TH-400 transmission. The 4L60 features a cast-aluminum case and an electronic control module (ECM) responsible for shifting. With four forward gears and one reverse gear, it offers smooth and efficient shifting. The first-generation 4L60 included a lock-up torque converter for improved fuel efficiency and hydraulic pressure control for smooth shifting and extended transmission life.

In 1996, the second-generation 4L60 was introduced with upgrades to enhance performance and durability. These upgrades included a redesigned sun shell, input drum, and planetary gear set, improving shifting and overall transmission performance. Notably, the 4L60 can handle up to 375 lb-ft of torque, making it suitable for high-performance vehicles.

Over time, the 4L60 has become more reliable and efficient. Advanced technologies like electronic pressure control have been incorporated into the latest models, providing greater precision and control over shifting. Overall, the 4L60 transmission is known for its reliability, durability, smooth shifting, improved fuel efficiency, and ability to handle high torque. It is a popular choice for both commercial and personal applications in GM vehicles.

Additional features and benefits of remanufactured 4L60 transmissions include:

• Remanufactured and improved torque converter included with every transmission.
• Torque converters are tested for leaks, lock-up, concentricity, and balance to eliminate front seal leaks, vibration, and premature bushing wear.
• Fully remanufactured valve body, with a complete system correction and recalibration kit, independently tested.
• Wear-prone valves are restored to stringent specifications and vacuum tested for proper function.
• Each remanufactured transmission is subjected to hot, cold, load, and simulated road testing using the proprietary CARS dynamometer program.
• All remanufactured transmissions come with a no-hassle nationwide warranty, providing peace of mind.

Technical updates and modifications to address OE flaws in the 4L60 transmission include:

• Installation of a complete system correction and recalibration kit to address several OE flaws, including updates to servos, the PR system, and valve body accumulators.
• Use of oversize PR valves to restore hydraulic integrity.
• Updates to TCC control valve, TCC regulator valve, and Actuator Feed Valve to address common wear problems.
• Upgraded 1-2 Accumulator Pistons made of aluminum, replacing OE plastic pistons that can cause premature clutch failure.
• Qualification and machining process for Tru-Flat stator.
• Upgraded sun shells to a stronger and more durable design, eliminating common OE failures.
• Installation of a High Energy 2-4 band to increase durability over the OE design.
• Upgraded High Energy 3-4 clutch pack from 6 to 7 clutches to enhance durability and torque capacity.
• Completely remanufactured pump with new line bore bushings to eliminate leaks and provide superior flow and durability.
• Fully remanufactured and improved torque converter tested for leaks, lock-up, concentricity, and balance, surpassing OE requirements to prevent front seal leaks, premature bushing wear, and vibration.
• Implementation of all-new custom-spec bushings to improve internal fluid flow control and pressures.
• Cold and hot testing of every transmission using a proprietary dynamometer testing program, including fully synthetic automatic transmission fluid and a filtration system.