Dominic,

The key difference with synthetic oil is the "base stock" from which it
is made.  Synthetic  base stocks are made in the lab and have a much
more uniform chemical composition, which really means more of the long
chain molecules that provide lubrication.  As temperature and
particularly pressure in a transmission break down these long chains the
better an oil with a high concentration of them will perform over a
longer period.

Mineral oil base stocks are a distillation of crude oil and a mixture of
many different molecular lengths. As these break down the concentration
of the long chains drops off more rapidly.

So, find a pure synthetic locally if you can, or mail order the Red Line
MTL.  You only have to change it every 50,000 to 60,000 miles.  If you
don't use synthetic change your mineral based oil every 20,000 miles.
--
Stuart MacMillan
Manager, Case Program
800-909-8244 ext 208

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