Cadillac CT4 2020-present 8L45 Transmission Specifications

The 8L45 transmission is an 8-speed automatic transmission designed for rear-wheel drive applications. It features a gear ratio spread of 7.26:1 for optimal acceleration and fuel efficiency. The transmission is compatible with the Cadillac CT4's 2.0L and 2.7L turbocharged engines, providing smooth shifting and responsive performance. It is designed to handle up to 369 lb-ft of torque and is paired with a centrifugal pendulum damper for reduced NVH. The transmission fluid capacity is approximately 8.5 quarts (7.9 liters) of GM-approved dexos1 full synthetic ATF.

Regular maintenance is essential for the longevity and performance of the 8L45 transmission. The recommended maintenance schedule includes transmission fluid changes every 30,000 to 60,000 miles, depending on driving conditions. Inspections of the transmission pan gasket, cooler lines, and fluid level should be performed annually or every 15,000 miles. Additionally, the transmission filter should be replaced every 30,000 miles. Always use GM-approved dexos1 full synthetic ATF for fluid replacements. Proper maintenance ensures optimal shifting, prevents overheating, and extends the life of the transmission.

Replacing the 8L45 transmission requires specialized tools and expertise. Start by safely lifting the vehicle and removing the battery, air intake, and other components for access. Drain the transmission fluid and disconnect the cooler lines, electrical connectors, and shift linkage. Remove the transmission mounts and crossmember, then carefully lower the transmission using a transmission jack. Installation is the reverse process, ensuring all bolts are torqued to specification (approximately 45-55 ft-lbs for bellhousing bolts). Refill with GM-approved dexos1 full synthetic ATF and bleed the system to remove air pockets. Always refer to the service manual for precise instructions.

Common issues with the 8L45 transmission include slipping gears, erratic shifting, or unusual noises. Start by checking the transmission fluid level and condition, as low or degraded fluid can cause poor performance. Use a scan tool to retrieve any trouble codes from the TCM (Transmission Control Module) for diagnostic clues. Inspect the cooler lines for leaks or blockages and ensure proper electrical connections to the solenoids and sensors. If issues persist, consider replacing the transmission filter or solenoid pack. In severe cases, internal components such as clutches or the torque converter may need replacement. Always consult the service manual for detailed diagnostic procedures.

To optimize the performance of the 8L45 transmission, ensure proper transmission fluid levels and use GM-approved dexos1 full synthetic ATF for optimal lubrication and cooling. Avoid extreme temperatures and prolonged high-RPM operation, as this can cause overheating. Use the manual shift mode for sport driving to take advantage of the transmission's responsive shifting. Regular maintenance, including fluid changes and filter replacements, is crucial for maintaining smooth operation. For enhanced performance, consider aftermarket transmission tuning software, but ensure it is compatible with the TCM and does not void the factory warranty. Always follow manufacturer guidelines for modifications.