CHEVROLET CORVETTE C7 Z06 LT4 AUTO 6.2 Gearbox Transmission

Chevrolet Corvette C7 Z06 (LT4 6.2L), the factory-correct automatic transmission is the Hydra-Matic 8L90 8-speed paddle-shift transaxle. This unit is specifically engineered to handle the 650 lb-ft of torque produced by the supercharged LT4 engine.

Core Transmission Specifications

The 8L90 (RPO M5U) is a high-performance transaxle that features a magnesium casing for weight reduction and a high-capacity torque converter.

• Gear Ratios: Features a wide 7.0 overall spread, with a 4.56 first gear for aggressive launches and a 0.65 eighth gear for highway fuel efficiency.

• Shift Performance: Capable of world-class shift speeds (up to 80 milliseconds), which GM famously benchmarked against dual-clutch transmissions (DCTs) of the era.

• Torque Capacity: Rated for up to 738 lb-ft (1000 Nm), providing a safety margin over the stock LT4 output.

Key Identification Codes

When sourcing a replacement for Buy Mustang parts Ltd, you must match the alphanumeric broadcast code on the transmission’s ID sticker. Using a non-Z06 8L90 (e.g., from a Silverado or base Stingray) will result in incorrect shift points and potential internal failure due to different clutch pack counts.

• Common Z06 Identification Codes: 5U4L, 6U4L, or 7U4L (The first digit usually denotes the model year: 5=2015, 6=2016, etc.).

• Main Part Number: Often listed under GM #24274891 or #24283944 (superseded numbers).

Maintenance & Common Issues

If you are stocking these for resale or performing a swap, be aware of the following technical requirements:

• The “Mobil 1” Triple Flush: Early 8L90 units (2015–2018) were prone to a “shudder” caused by moisture absorption in the fluid. The industry-standard fix is a full flush using Mobil 1 Synthetic LV ATF HP (Blue Label).

• Programming (SPS): The Transmission Control Module (TCM) is internal. A replacement unit must be programmed to the vehicle’s VIN using a GM MDI tool and SPS2 software, or it will not engage gears.

• Cooling: The Z06 variant uses specific high-flow cooling lines. Ensure the thermal bypass valve is functioning to prevent overheating during track use.

Market Availability (2026)

• Certified Used (<30k miles): $2,600 – $3,200

• Remanufactured (GM Genuine): $4,200 – $5,100

• Core Value: $500 – $800