http://www.allpar.com/mopar/transmissions/fluids.html
Group three oils:
Group three oils are petroleum oils that have been hydroisomerized, "hydro-cracked" as it is commonly called. The most stringent level of petroleum oil refining. Much of the paraffin and impurities have been removed and its performance on any number of industry tests is substantially better than it's group two cousins.
Although it is not made from a synthesized, engineered molecule and as such is not a true synthetic oil, it does offer a portion of the benefits you would expect from a true synthetic and in fact is usually sold and marketed as a 100% synthetic product.
In fact the vast majority of synthetic oils on the market are actually made from group three oils because of a lawsuit a few years ago between Mobil and Castrol that totally changed the synthetic oil industry. Because of this lawsuit the buying public has largely been duped into believing that these oils are actually a real synthetic.
Here's what happened. Mobil Inc. makers of Mobil One sued Castrol Inc. makers of Castrol Syntec, accusing them of marketing a hydro cracked petroleum oil as a synthetic-which they were!
Mobil Inc. felt that Castrol Inc. had pursued an unfair market advantage because group three based oils are much less expensive to manufacture than true synthetic oils yet Castrol was marketing Syntec as a 100% synthetic product: Castrol could make it for less, sell it for less and un-fairly under cut all it's competitors in the synthetic oil market with a oil that was not truly a synthetic product.
In the end though, Castrol convinced the court that group a three-based oil has been sufficiently refined that it should be able to be marketed along with true synthetic oils. Basically the court expanded the definition of synthetic to include group three based oils.
Because the synthetic oil market is the fastest growing part of the lubricants industry, manufactures are eager to jump up and grab the profits that having that sexy customer grabbing word synthetic on the bottle bring.
Group three oils have no where near the performance of true custom engineered synthetic oils, especially in tempeture extremes where the men get separated from the boys so to speak!
As was stated before, the vast majority of what is being sold as synthetic is now really group three petroleum based oils-and the public for the most part doesn't know the difference. But now you do!
from
http://www.klotzwarehouse.com/index.php?show_aux_page=6
