* Engine Speed/RPM: The transmission shifts up to a higher gear when the engine reaches a certain RPM. This improves fuel economy by allowing the engine to run at a lower RPM at higher speeds. Conversely, it shifts down to a lower gear when more power is needed (e.g., accelerating uphill or passing).
* Vehicle Speed: The transmission also uses vehicle speed as a factor in determining when to shift. Higher speeds generally correlate with higher gears.
* Throttle Position: How much the accelerator pedal is pressed influences shifting. Aggressive acceleration will cause the transmission to hold lower gears longer to provide more power.
* Load: The weight of the vehicle and any cargo significantly affects gear selection. Heavier loads may necessitate lower gears for sufficient power, especially on inclines.
* Transmission Control Module (TCM): The TCM is the "brain" of the transmission. It constantly monitors all the inputs mentioned above (RPM, speed, throttle position, load, etc.) and uses sophisticated algorithms to determine the optimal gear for the current driving conditions. It aims for the smoothest and most efficient gear selection possible.
* Upshifts vs. Downshifts: Upshifts increase fuel efficiency and reduce engine noise. Downshifts provide more power and engine braking (when decelerating).
In short, the Tahoe's automatic transmission is a complex system designed to seamlessly and automatically select the appropriate gear for optimal performance and efficiency based on a variety of real-time inputs.
