Converter Lockup Control

The B and M AUTOMOTIVE Converter Lockup Control (Part #70248) is a precision electronic module designed to manage torque converter engagement in automatic transmissions, giving you direct command over one of the most critical power transfer components in your drivetrain. Whether you're building a high-performance street machine, tuning a drag racing platform, or seeking to optimize fuel economy on a daily driver, this control unit lets you fine-tune converter lockup timing to match your specific driving demands. This module is essential for enthusiasts who want transmission responsiveness and efficiency that factory tuning simply cannot deliver.

The converter lockup mechanism eliminates parasitic slip between the torque converter and transmission input shaft, reducing heat generation and improving power delivery once engine RPM and vehicle speed conditions are met. B and M's controller intercepts factory solenoid signals and applies real-time logic to hold lockup across a broader RPM window, allowing you to maintain mechanical coupling during acceleration, cruising, or deceleration—precisely when you need it. The compact 0.95 lb module (measuring 5.7 x 5.45 x 7.25 inches) installs cleanly in engine bay or under-dash locations without requiring transmission pan removal, making it a straightforward retrofit that pays dividends in drivability, shift quality, and transmission longevity by reducing friction and thermal stress.

Transmission builders, performance shops, and DIY mechanics working on 700R4, 4L60E, 4L80E, and other GM automatics benefit most from this controller, especially when paired with engine tuning or converter upgrades that demand synchronized lockup behavior. Installation requires basic wiring skills and familiarity with transmission electrical connectors; the unit intercepts solenoid grounds or supply voltage depending on your transmission generation. Real-world testing confirms improved transient response, reduced converter temperature, and better fuel economy—key metrics that matter whether your goal is drag strip consistency, street performance, or everyday reliability.