This performance upgrade component modifies the automatic transmission to allow complete driver control over gear selection. It replaces or modifies the existing assembly, enabling upshifting and downshifting solely through manual input, eliminating the automatic shifting functions of the transmission. This setup is typically employed in high-performance or competition vehicles where precise gear control is desired.
The appeal of this modification stems from the increased control it offers over engine RPM and torque output. This level of command is particularly advantageous in situations where optimized performance is paramount, such as drag racing, off-road driving, or towing heavy loads. Historically, this level of transmission control was only available in manual transmissions; this modification bridges the gap, offering similar functionality in an automatic transmission.