transmission lube

Brett Dikeman brett at
Wed Mar 5 13:03:22 EST 2003

At 4:45 PM -0800 3/4/03, Linus Toy wrote:
>FWIW--German Transaxle in Bend, OR, will NOT warranty their work on
>a VW/Audi tranny if it was filled w/ GL-5 gear oil OR ANY
>MULTI-GL-rated gear oil--use only a straight GL-4.  Their
>recommendation is either Redline MTL or OEM Audi oil

We just went over this whole Amsoil GL4/5 business a few months ago,
see below, I've included the message from Eric.  In any case, I found
the rear diff size- I thought I might have asked about it back in
December, and I was right, I did- 1.7 liters(from daswolfen at
Looks like you'd need a total of 4.9 liters, which seemed odd until I
had a hunch and fired up the calculator- 4.9l is almost exactly 1 UK
gallon(1.077 UK gal).

The only remaining question is whether it is appropriate for the rear
differential as well; I emailed Amsoil's tech line and early this
morning had an answer- they confirmed AGR 75W90 is appropriate for
the 200q20v, and said that yes, it's also appropriate for the rear

As for "the Bentley does not recommend a change interval", that's
correct, and one of the reasons there was a TSB issued stating that
lifetime tranny fluid isn't quite lifetime(there's also a TSB stating
that fluid can leak out of the transmission over time and cause
seizure).  Manufacturers have alwyas tried to claim one fluid or
another is "lifetime", and almost exclusively, they've been wrong
every single time.

As to people "imagining" an improvement in shift quality and syncro
action due to "lighter wallet syndrome", well Bernie, I find that
suggestion laughable, particularly here in the northeast where temps
drop into the single digits, and transmission fluid changes to syrup;
syncro performance is -easily- gauged.  When my old 5000 had the
transmission fluid changed over to fresh Mobil 1 synthetic, I noticed
an immediate improvement in syncro mesh times in cold weather.


>To: 200q20v at, qlist at,
>	Stephane.Livolsi at
>Subject: Amsoil Transmission Oil (Gear Lube) - 75w90 GL2-GL5, MT-1
>vs. 80w90 GL4 MT-1
>From: Eric_R_Kissell at
>Sender: 200q20v-admin at
>Date: Thu, 12 Dec 2002 17:29:59 -0500
>I called the AMSOIL Tech Line.  I discussed the rating of their 75w90 GL2
>through GL5 MT-1 rated transmission oil and whether this oil was
>appropriate for VW/Audi manual transmissions.
>The short answer according to the man I spoke with is YES.
>According to the AMSOIL tech rep, AMSOIL 75w90 does have additives to
>achieve the GL5 rating, but it also contains buffers to prevent these
>additives from attacking soft metals such as brass synchro rings, which is
>part of what the MT-1 rating tells you. The technical representative from
>AMSOIL said that their 75w90 transmission oil with a GL2 through GL5 &
>MT-1 rating was suitable for the Audi/VW transmissions because of the MT-1
>rating and the GL4 rating.
>He cautioned that other manufacturers might not use buffers in GL5 rated
>synthetic oil and that he could not speculate about the suitability of
>other GL5 rated synthetics with soft metals.
>He also said that if anyone was really concerned about the additive
>associated with the GL2 through GL5 rating of their 75w90 in spite of the
>protecting buffers, they could choose to use their GL4 MT-1 rated 80w90,
>which would also work fine.
>I was curious about the MT-1 rating, so I dug a bit deeper on the
>internet.  I found a site that talked about driveline lubricants:
>A link in this writing summarized GL5 testing versus MT-1:
>This shows that MT-1 and GL5 have little overlap in test requirements, so
>if an oil has both ratings it has satisfied the requirements of more test,
>which should be a good thing.  One of the MT-1 test that is not required
>under GL5 is ASTM D-130, which is stability of copper and copper alloys.
>This may be the "soft metal test" that the AMSOIL tech rep mentioned. I
>did not look at ASTM D-130 to understand if it means that brass synchros
>will be OK, but my guess is that brass counts as a copper alloy, so a MT-1
>means OK with brass.
>In summary, according to AMSOIL the buffers in the AMSOIL 75w90 GL2
>through GL5 MT-1 transmission oil should protect the brass in the VW/Audi
>gearbox. AMSOIL also has a 80w90 that is rated GL4 MT-1 which will work in
>the VW/Audi gearbox without any GL5 additives requiring buffers if this
>concerns you.
>I cannot comment about how AMSOIL gear oil compares to Redline MTL or
>MT-90 in terms of the Redline claims about having enough friction for
>proper synchro engagement. I am planning to try AMSOIL 75w90, 80w90 and
>maybe Redline MTL to see for myself when I have time.

"They that give up essential liberty to obtain temporary
safety deserve neither liberty nor safety." - Ben Franklin

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