Review on Enhance Performance with Ford CM19546A1 Friction Modifier by Leonard Beard

Excellent additive for older cars with blurry, noisy differentials. There are other uses reported by various commenters - read what they say. Although it is packaged in a secure container, the smell oozes from the bottle and you and your family will quickly find out when you bring it home. Keep it in a garage or outbuilding to avoid odors. (A strong smell means it's working very well.)