There are a lot of mechanics and others who not only think this is good for your fuel system, there are even people who will fill up their fuel filter with it when they change filters.
For proper fuel additives, and the benefits there of, I would stick with: Stanadyne, which is the only diesel fuel additive actually made by a company that manufacures diesel fuel pumps and injection systems, Redline Diesel Fuel Catalyst/85+, or the Lubro Moly products. Redline and Lubro Moly are sold by PartsShop.
A few months ago, I did a lot on research on this subject, and here's a quote from:
http://www.goa-northcoastoil.com/tips/atfchnges.html
"At elevated operating temperatures, ATF oxidizes, turns brown and takes on a smell like burnt toast. As heat destroys the fluid s lubricating qualities and friction characteristics, varnish begins to form on internal parts... YOW! I don't want to burn that stuff in MY engine!
That would be elevated temperatures as in when combusted...
Here's the whole thread is you really need to do some reading:
http://www.peachparts.com/shopforum/showthread.php?threadid=13873