GM 8L90 transmission

Specifications

The 8L90 transmission is an advanced 8-speed automatic developed by General Motors for high-performance rear-wheel-drive applications. Introduced as part of GM’s newer automatic transmission family, the 8L90 is known for its compact design, impressive torque capacity, and lightning-fast shift performance. Built with a durable aluminium case, reinforced internal components, and an efficient gear set architecture, the 8L90 delivers both strength and refinement for modern muscle cars, trucks, and performance platforms.

The 8L90 transmission comes in several variants tailored for different vehicle platforms, power levels, and drivetrain configurations. While all versions share the same core architecture, an 8-speed, electronically controlled automatic with a compact gear set design, each variant is calibrated and equipped to meet the specific demands of its application. Differences typically include bellhousing patterns, torque converter specifications, gear ratios, cooling provisions, and internal clutch materials.

Transmission Variant   

M5U

The M5U is the most performance-oriented version of the 8L90, commonly found in vehicles such as the Chevrolet Corvette Stingray, Camaro SS, and Cadillac CTS-V. This variant features aggressive shift mapping, a high-capacity torque converter, and clutch materials designed to withstand rapid gear changes under heavy load. Its calibration prioritizes crisp, high-RPM upshifts, fast throttle-response downshifts, and minimal torque loss, making it ideal for high-horsepower sports cars where acceleration and shift speed are critical.

M5T

The M5T variant is built specifically for trucks and SUVs, including the Chevrolet Silverado, Colorado, GMC Sierra, and certain full-size utility models. It features enhanced durability for towing and heavy-load use, with a torque converter tuned for strong low-RPM torque multiplication. The M5T also includes reinforced clutch packs and cooling strategies to handle prolonged stress, making it the preferred option for work environments, off-road use, and hauling.

M5X

The M5X serves as a balanced transmission variant used in premium GM models such as select Cadillac sedans and crossovers. This version blends performance with refined drivability, offering smoother shift transitions, quieter operation, and torque converter tuning designed for comfort without sacrificing responsiveness. The M5X variant is calibrated to deliver quick, clean shifts while maintaining the upscale ride quality expected in luxury vehicles. 

Frequently Asked Questions