Another major departure from past GM transmissions is that the 6L80E has no bands-just clutches-and relies heavily on electronics for all aspects of operation. By eliminating the bands, GM reduced the number of torque-handling components inside the transmission while also improving shift quality. The downside is that the timing of clutch engagement and disengagement, as well as clearances, must be very precise in order to prevent internal damage. Even at stock horsepower levels, Circle D reports that properly tuning the 6L80E is critical to transmission longevity. "The 6L80E is a clutch-to-clutch unit, which means that unless one clutch engages at exactly the same time that another clutch is disengaging, the transmission will bind up. That's where the electronics and tuning come into play," explains Kyle. "When GM builds the 6L80E at the factory, it installs a control module directly to the valve body. It houses all the pressure control solenoids, shift solenoids, and the transmission control module in one sealed unit. There are tons of electronic adjustments that can be made to alter clutch pressures and apply times for durability. The factory tune is good until you start putting more power through the trans. Once that happens, the clutches start slipping on initial apply, which messes up the timing. Depending on a customer's needs, we can modify the transmission control module so it's custom tailored to a specific application using HP Tuners software."