Information I found on the internet...

From the following site: http://www.dieselpage.com/art0898ua.htm

A known practice especially amongst truckers is the adding of Automatic Transmission Fluid (ATF) to diesel fuel. According to tests performed by the Society of Automotive Engineers (SAE) and the International Standards Organization (ISO) the lubrication benefit from ATF is very slight. The effects and consequential damage that could result from the use of ATF in diesel fuel has not been determined. The addition of ATF in diesel fuel also changes the chemical make-up of the diesel fuel which could result in penalties for use of a NON-EPA approved fuel. ATF is not an additive and it's use could result in costly repairs and/or fines, a more proven and effective conditioner should be used when treating diesel fuel..... More on this to come in the next few months..

Jeff