Review on GTMOTOR AFM RA003: The Ultimate Fuel Management Disabler for GM Vehicles by Tim Bunker

Although the instructions say to disconnect the battery I had no trouble connecting it with the key off. As mentioned here, this is perfect for Silverados. This saves the hassle of overshifting while the V4/V8 mode tries to take over. Now the transmission can hold up in my truck and I have to think that was the 'problem' the Silverados had with early transmission failures in certain years. And I didn't feel any noticeable difference in gas mileage. So for the price. Why not !?!?