Take a look at this! 
Chevron Claims To Have a Special Formulation Hydraulic Fluid.......15 Years Behind AMSOIL!
(This article appeared in Lubes 'n' Greases Magazine- July 2000 in the  Letters to the Editor Column)

Dear Lubes 'n' Greases,

I would like to respond to the article by Joe O'Neil about the new "all season synthetic"  tractor hydraulic transmission fluid from Chevron ("A Fluid For All Seasons, " April 2000, page 30).  You quote Chevron's Jack A. Zakarian as stating that Chevron patented the product because of "the formulation is so special."  In fact the Chevron patent reveals the product is no more "synthetic" than is the reformulated Castrol Syntec, i.e., it apparently contains no true synthetic base oils and represents yet another example in a disturbing trend of taking advantage of the recent looseness in the definition of what constitutes a synthetic oil.

In addition, the opening statement of the article would have us believe that equipment operators have had no choice but to change fluids with the seasons, and that Chevron has recently saved the day with the introduction of All-Weather THF.  Not only that; Mr. Zakarian states that the John Deere J20C and the J20D specs could not be met by one fluid until the introduction of Chevron THF.

In fact, AMSOIL Inc., in Superior, Wis., has just such a product.  Synthetic Tractor Hydraulic/Transmission Oil, ATH, which exceeds both the Deere specs, can certainly be considered "all weather", it is a true synthetic, and the product has been available for over 15 years!

Paul B. Buck

Industrial Chemicals & Lubricants Inc., Duluth, GA