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Re: gearbox fluids

To: <spitfires@autox.team.net>, <sdspitfire@worldnet.att.net>
Subject: Re: gearbox fluids
From: "Nolan Penney" <npenney@mde.state.md.us>
Date: Thu, 15 Mar 2001 06:34:19 -0500
Laycock overdrives will work with just about every fluid known to man.  I have 
read their own factory recommendations for the D type, which ranged from 90 
weight EP gear lube, down to 10-30 motor oil.  It depended on the transmission 
they were installed behind.  Volvo, with their J type, goes so far as to 
recommend ATF.  All should work just fine.

The guy who talked to you about friction modifiers is correct.  This is 
significant and quite comparable to the dangers of using the wrong type of oil 
in a limited slip differential.  The overdrive and limited slip clutch pack are 
almost identical in their operation and their materials.  This is why if you 
put generic hypoid gear oil in the differential of a car with limited slip, you 
get all sorts of problems.  It screws up the friction.  Same with a laycock 
overdrive probably.  Hence the warning about friction modifiers.  

Probably the simplest and easiest way to ensure you don't run a wrong oil in 
one is to check the bottle you are using and make sure it does not say it's 
suitable for differentials.  If you can't find that, put some motor oil in the 
transmission.  Straight 30 or 40 weight if you like it straight, 15-40 or 20-50 
if you like a blend.

>>> "Ken C" <sdspitfire@worldnet.att.net> 03/14 6:00 PM >>>

When asked about the products one can find in Kragan (a local auto parts
discount store), he would not recommend any. When asked about Redline
products, OK for regular transmission use, but not for o/d use. He then went
into a long discussion about 'friction modifiers' and other additives
commonly found in most of the gear lubes. Of course, I just nodded, but
really had no clue what he was talking about. He convinced me and I just
want to pass it along. Basically, your choice in a regular transmission, be
very picky with an o/d unit, the o/d clutch is very expensive to replace.

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