Miata Mailing List: July 1993, Message #24
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   From: hazmat@motor.arl.army.mil (Matt Bennett)
Subject: Re: Transmission Oil
   Date: Fri, 2 Jul 1993 16:47:50 -0400


Steve writes:

>> From: Mike Rother 
>> Subject: Transmission Oil
>> Date: 	Fri, 2 Jul 1993 09:27:48 -0400
>>
>> 	"We put in 80W-90 or ATF - depending on what comes out of
>> 	 the transmission."
>>
>> The service person went on to explain that many Mazdas (incl Miatas)
>> come from the factory with ATF in the manual transmission - to make
>> cold-weather shifting easier.
>>
>> What do you think of this?

>I hope he said this with a smile.  I think (IMHO) that it's either a joke
>or the guy is full of sh*t.  The only reason ATF should come out of the
>tranny is if it's an AT (Automatic Tranny).  ATF (at least in my understanding
>flame me if I'm wrong) is a hydraulic fluid, not a lubricating fluid.
>It's properties are consistent with a hydraulic fluid, not a lubricant, and
>as such would not be suitable for manual transmission lubricant.

This is not necessarily true. ATF can be used in manual transmissions.  I
remember that the manual tranny on my Ford Escort(83) used type F ATF... I
still have half a case of the damn stuff in my shed.  I am under the impresson
that ATF is a great lubricant, and hydraulic fluid.  In fact, Honda specifies
the use of ATF in the forks of some of it's motorcycles.  There has also been
a lot of debate on the use of ATF in the gearboxes of two stroke motorcycles.
It has one advatntage: it's a different color than oil, so it makes
it easy to tell which is leaking :-)

We get to the vital question: What does the service manual specify?  That's
the source to trust.

Matt