GL4 or GL4/5 Transasxle fluid

[Royal]

OK guys, I’m doing my fluid changes and decided to change the oil in my transaxle (VW).  I’ve read a lot where opinions say don’t use GL5 because it contains additives that harm our older gears.  I think they are talking about synchronizers, but anyway, the opinions seem to be it is safest not to use anything that even references GL5.  I went to 5 auto parts stores today and only found one EP GL4 oil that did not say GL5 on it.  So, assuming that all EP API GL4 oil is the same, I bought it.  Bravo oil at Carquest.  Many GL4 oils may be available where you live, but this was my experience.  

     So, the question is:  Does anybody really know if GL5 is ok?  Most of the articles and posts that I read were pretty old and maybe the harmful stuff in GL5 is no longer there??

     I’m putting the GL4 in this year, but it seems that it is getting hard to find.    

[edward ericson]

I thought 75w-90 gear oil . . .?

[newkitman]

I finished my transaxle about a month ago. I’ll check what I used but I think it was 90 wt gear oil. I’ll report back later.

Allen Caron
VW based 53MGTD - "MoneyPenny"
"If one thing matters, everything matters" - from the book The Shack

[Royal]

I’m sure that you both used 90+/- gear oil.  Me too.  The question is the GL4 stuff or the GL5 stuff?  

[edward ericson]

Hot debate, looks like. I will get some GL-4 for Bridget.

BTW. Tranny oil is like a 60,000 mile change. My car doesn’t even have that many miles on it. (Though not sure about the transaxle).

I’m thinking this is a one-and-done job.

edsnova2013-03-13 15:07:22

[Royal]

Yeah Ed, I know.  The book says every 60k miles or every 40 years, whichever comes first.  😆

[Royal]

Ed, Under your “Hot Debate” link, you found, perhaps, the only article on GL4 vs GL5 that I had not read.  Your article is the best and also the most recent.  The TD forum comes through again.  The GL4 Carquest oil that I had found is single 90 weight.  I guess I’ll take it back and continue my search for a 80W90.  Thanks.  

[edward ericson]

Aircooled.net has Amsoil synthetic. pricey at $11 a quart but what do we need? 2, maybe 3 quarts?

I think I also need a 17mm allen wrench.

[Royal]

Ed, not so fast with the synthetic.  It is my understanding that the stuff may be so slippery that the synchronizers won’t grab and synchronize.  

[Royal]

Re a 17 mm allen wrench:  I have a pretty good supply of not so common tools but no 17mm allen.  I did, however, find an el’cheapo spark plug socket with a 17mm hex around the top where you put the rachet.  I guess the hex is in case you need to use a metric Crescent wrench, if you can’t find your 3/8″ drive Snap-on.  Perhaps you can be so lucky.  (That plus a small pipe wrench around the outside of the socket do the trick.)

[newkitman]

I have the an almost empty Carquest GL4 gear oil. I’m good with that.

Allen Caron
VW based 53MGTD - "MoneyPenny"
"If one thing matters, everything matters" - from the book The Shack

[edward ericson]

More fun with API specs:

So I went to the NAPA today and bought three quarts of gear oil. this stuff was rated GL-4/GL-5. Went back to the innerwebs tonight to study the matter further (It’s cold in the garage and I’ve not yet found anything like a 17mm allen hex to open the tranny up).

Appears that the GL-5-eats-brass-synchros problem was a decade passed, superseded recently by the magic of chemistry. Quoting from this 2010 post (from a user named “full of Mencken,” so you know he’s to be trusted in all matters, temporal, moral, technical and general):

“another site i just looked at explained it thusly:

http://www.thesamba….t-276529–.html

“I sent a tech message to the Amsoil tech guy. His response stated the
history of how that myth got started by the ignorant VW people. When
GL-5 first came out it was indeed corrosive to brass syncros. But only
at temps above 250ºF. Now since it is impossible to get any street
driven gear oil to that temp (It is hard to get engine oil that hot!),
there will be no problems using regular GL-5. However, just to satisfy
the ignorant masses, the API came up with another added rating, called
MT-1 which is tacked onto the end of all GL-5 oils you can buy today.
With this MT-1, GL-5 oil is not corrosive at any temp.

The difference between GL-4 and GL-5 is the extreme pressure capability.
On surfaces that have high pressure where metal to metal contact will
happen, the GL-5 is way better at protecting. Spider gear teeth and side
gear teeth are one place where GL-5’s better EP rating is desperatly
needed. I’ve got 5-6 Bus 091 ZFs in my garage right now that have
suffered significant wear on the gear teeth from probably using GL-4.”

So, there you have it. Widman, whose late 2009 paper is downloadable here. Or a random-but-literate internet guy who apparently has taken apart more than one VW Bus transmission in the past few years.

Sorry I asked.

edsnova2013-03-14 20:26:32

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