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RE: overdrive lube

To: tr3driver@comcast.net, triumphs@autox.team.net
Subject: RE: overdrive lube
From: "John Herrera" <jrherrera90@hotmail.com>
Date: Thu, 10 Nov 2005 11:34:40 -0500
> > I was reading some of the topics on the Quantum Mechanics
> > website, and saw
> > that John Esposito recommends using non-detergent 30W oil in the OD and
> > gearbox rather than the TR-specified 90W hypoid gear oil.
>
>Note that the factory recommended 50 weight (rather than 30 weight) in hot
>climates (at least for TR3, I assume TR6 is the same), and I do live in a
>hot climate.  The multi-weight oil seems to let the gearbox shift better
>when cold than straight 50 weight does.

It is interesting to note that SAE Grade 30 motor oil and SAE Grade 90 gear 
oil have about the same viscosity. That's because the SAE measures viscosity 
of motor oil and gear oil on different scales.

It is incorrect to call oil 30 weight or 50 weight. Weight has nothing to do 
with the SAE grade. The SAE grade is a measure of viscosity.

It's also incorrect to call an oil multi-viscosity. An oil has only one 
viscosity at a given temperature. You should say multi-grade. The W in 
20W-50 means Winter. This is saying that the oil meets the viscosity spec 
for Grade 20 when it's cold and meets the spec for Grade 50 when it's hot.

Wow, never thought I would correct Randall on anything. But this is my pet 
peeve.

Well, this and flowing Volts. Can you have multiple pet peeves?

John H.


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