More than likely, the Equal-I-zer still made groaning noises, it just wasn't noticeable to the OP any more. It quieted down, but not loud enough to be herd from inside the vehicle. (my guess). Just for an FYI, most of the time, I never hear mine groaning and popping from inside my truck. The my diesel engine is somewhat noisy with windows open and with windows closed, it really sound proof inside. It's only when I have my wife back up or pull forward and I'm outside the truck I hear it. With the little pads, it's quieted down and not noticeable, or else, I'm just so use to it now, I simply don't hear it any more.