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Subject:Re: GL5 vs GL4 Gear Oils
From:John Rodgers
Date:Tue, 12 Mar 2002 16:18:00 -0600

AA Transaxle wrote:

>   I recommend every 30K mi. even for Redline. The long chain molecules in
> all
> the varieties of oils do wear out (as I have been told) and fresh oil is
> cheap insurance.

Daryl, I agree with you. I never have understood why people don't want to
chainge the oil in the transmissions and in more conventional vehicles, even
the rear differential.

Years ago I worked in an oil analysis laboratory at Ft Ruccker, AL. The home
of the Army's helicopter command. We had a test program where the guys would
go out and hover those machines in a sand pit for hours and hours. Every time
they stopped we got a shipment of oil samples form all the various
transmissions and sumps on the engines. it was amazing to see the changes in
the oil. And YUP!, the long chain molecules are chopped to pieces, and lose
their protection qualities.
We got pretty good at predicting rotor blade transmission failures. Did a lot
of spectragraphic analysis on the lubes and plotted the elements on charts
maintained on each aircraft. You could always tell a spike, and a rapid rise
in indicator metals always predicted  a failure shortly.

John Rodgers
88 GL Driver