When the NOCO Boost GB40’s Boost LED is off, the unit cannot detect a battery; the documented explanation is a connected 12-volt lead-acid battery below 2 volts. That reading tells you about battery detection, not the exact condition of the battery or the cause of every light pattern.

If your Chevy with a 6L80 transmission is shuddering between 40 and 70 mph, you are likely experiencing a known issue related to the torque converter clutch or fluid condition. General Motors has issued specific service bulletins addressing this exact behavior, confirming that a vibration during…