Miata Mailing List: April 1994, Message #78
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   From: Andy Poling 
Subject: Gearbox and Diff Oil (fwd)
   Date: Tue, 5 Apr 1994 15:58:05 -0400

Netcom's still a headache...

---------- Forwarded message ----------
Date: Tue, 5 Apr 1994 12:33:14 -0400
From:miata@jhunix.hcf.jhu.edu
To: andy@jhunix.hcf.jhu.edu
Subject: Gearbox and Diff Oil


Rejected message sent to miata@jhunix.hcf.jhu.edu by NETCOM.COM!UUCP
follows.
-------------------------------------------------------------------------------

> I have had many replies as to the type of G/Box oil to use in preference to
> Mobil SHC 75w-90.  Everyone seems to recommend AMSOIL or Redline none of
> which are available in Australia any further suggestions.Only the large
> companies oils such as Mobil, Castrol, Penrite, Agip, BP, Shell, Caltex,
> Valvoline, STP are available.
> A J K

I called up Redline, and they'll ship to you where ever you are (yes, even
Aus).  All you need is your visa credit card and Redline's phone number out
here in California

	510 228 7576

9:00 am (we just moved our clocks ahead one hour this weekend) here in 
California is about 2:00 am in Sydney.

I just put MTL in my transmission and it's *great* !!  I can effortlessly
down shift 2 to 1 at 20 mph (32 kph).  The 1-2 shift is pretty darn smooth
(it just drops right in, no "click" like before), although the most
dramatic difference is in the down shift between gears.

I also put 75W90 in my differential.  This is one very happy car (and
driver ;-)

The MTL is reddish and feels about as thin as motor oil.  It doesn't even
smell like tranny oil (must be because it is a GL-4 and not a GL-5 oil).
Although the manual calls out 2.1 quarts of oil, I think I was only able to
pump in 1.9 quarts.  I drove the car on the freeway and around town for about
30 minutes just before changing the tranny and diff oil to get the transmission 
nice and hot and let it drain for at least 1 hour.  I'm wondering if some oil
stays in the extension or in the shifter part of the tranny.  The car was
level and resting on 4 jack stands...

The diff seemed to hold the 0.7 quart as the manual predicted.  The 75W90
is golden, significantly thicker (harder to pump), and smells like gear
oil.

I strongly recommend replacing the washers as the manual does ($0.85 each),
the original washers were quite deformed.  I torqued the drain plugs to spec 
(~ 35 ft-lbs / 45 N-m).  There is one washer on the tranny, and two (one drain,
one fill) on the diff.

Although it is probably cheaper to buy local than from Redline, the oil is
going to go about 30k miles (I can rationalize anything for my Miata).  Small
price to pay each 2 years for smoother shifting.

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Eric Jacobs                              Internet:  ej@silma.com
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SILMA Inc.                               Fax: (408) 725-8955

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