What is the toyota rav4 humming noise?

Owners of the 2007 Toyota RAV4 have complained of "humming" or "whining" noises as they accelerate or use cruise control between 30-40 miles per hour. Sounds are especially prevalent when going downhill and most associated with the V6 engine design. They tend to disappear momentarily if the foot is taken off the gas pedal. Some dealers insist the 4 X4 ECM needs replacement, but drivers still notice faint humming after repairs are completed. Toyota has acknowledged the problem in models of the 2006 “ 2008 V6 RAV4s, but continues to claim these sounds are part of normal vehicle operation. Some drivers have successfully re-aligned and switched out the drive-shaft to eliminate the humming noises.