GL5 in the t-176 - Pirate4x4.Com : 4x4 and Off-Road Forum

eighty2cutass · 02-11-2008, 12:19 PM

I have read everywhere that GL5 will eat brass bushings/synchros because of the high sulfur content. I mistakenly put in GL5 the other week when I put the rebuilt transmission in and it ran fine. I let it sit for a week and now it grinds when I have it in 4th gear pretty bad. It is obviously my mistake, but how fast does this stuff actually eat synchros?

jeffy · 02-11-2008, 04:13 PM

Well, if you still have the bottles you'll want to check and see if the GL-5 has the MT-1 designation or not. GL-5/MT-1 is syncro friendly and was reformulated soon after the whole GL-5 issue came up.

Otherwise, it's hard to say how fast your syncro's will be damaged. You'll have to drain it and check for gold.

praetorian · 02-11-2008, 04:57 PM

Now when you say, MT-1 is syncro friendly does that mean brass/bronze syncros, like in the AX-15>

jeffy · 02-11-2008, 05:04 PM

Yes, MT-1 designation means it's safe with yellow metals like copper and brass, ie. syncros.

atblis · 02-12-2008, 06:21 AM

If you trackdown the Amsoil white paper on gear oils, they actually run the copper corrosivity test on a bunch of GL5s. Most of them pass just fine. I believe the GL5 spec isn't required to pass that test. Doesn't mean it won't, doesn't mean the manufacturer didn't do it, just that it isn't in the spec.
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atblis · 02-12-2008, 06:31 AM

If you trackdown the Amsoil white paper on gear oils, they actually run the copper corrosivity test on a bunch of GL5s. Most of them pass just fine. I believe the GL5 spec isn't required to pass that test. Doesn't mean it won't, doesn't mean the manufacturer didn't do it, just that it isn't in the spec.

I wouldn't rely on the MT-1 spec to tell you anything. In fact, it is intended for transmissions that are non synchronized. I can't find the tests it has to pass for the MT-1 spec so...

A GL4 is what you want.
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atblis · 02-12-2008, 06:33 AM

According to Amsoil

Quote:

Also, both MT-1 and MIL-PRF-2105E require a
more severe cooper corrosion test (ASTM D-130) than
MIL PRF-2105D.

It looks like the MT-1 does incorporate the D-130 test.
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jeffy · 02-12-2008, 08:22 AM

Quote:

Originally Posted by atblis

If you trackdown the Amsoil white paper on gear oils, they actually run the copper corrosivity test on a bunch of GL5s. Most of them pass just fine. I believe the GL5 spec isn't required to pass that test. Doesn't mean it won't, doesn't mean the manufacturer didn't do it, just that it isn't in the spec.

I wouldn't rely on the MT-1 spec to tell you anything. In fact, it is intended for transmissions that are non synchronized. I can't find the tests it has to pass for the MT-1 spec so...

A GL4 is what you want.

Hmm, interesting. I looked up the Amsol test for Gear oils. (nice find.) http://www.amsoil.com/lit/g2457.pdf

This is probably the one you're referring to.

Mopar, Royal Purple and Lucas didn't pass but all of the others did. Page 17.

rockrknockr · 02-12-2008, 03:03 PM

i don't see how the GL-5 could "eat" synchros in a week

even the whole theory about it causing damage to synchros is hard for me to fathom but WTF do i know. i can say though that my AX15 works so much better with pennzoil synchromesh instead of the GL-5 75-90 shit. i might attribute to the pennzoil seeming a bit lighter weight than 75-90 even though i read it to be 80w. can't believe everything you read/hear

atblis · 02-12-2008, 05:02 PM

What brand of GL5 were you running?

It varies. I've heard rumours of failures within maybe 5-10 k miles. Not weeks though.

It appears that most GL5s are fine for brass synchros. That's probably what makes this whole thing so confusing.
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02-11-2008, 12:19 PM	#1 (permalink)
eighty2cutass Fly like an eagle... Join Date: Aug 2005 Member # 52761 Posts: 86	GL5 in the t-176 I have read everywhere that GL5 will eat brass bushings/synchros because of the high sulfur content. I mistakenly put in GL5 the other week when I put the rebuilt transmission in and it ran fine. I let it sit for a week and now it grinds when I have it in 4th gear pretty bad. It is obviously my mistake, but how fast does this stuff actually eat synchros? __________________ TREC # 258 '81 AMC Eagle (Chocolate PopTart) Abrar: The Eagle makes a total of 400 hp (100 hp mechanical, 300 hp spiritual), so the parasitic loss is minimal.

02-12-2008, 06:21 AM	#5 (permalink)
atblis Registered User Join Date: May 2005 Member # 46937 Posts: 2,362	Yeah If you trackdown the Amsoil white paper on gear oils, they actually run the copper corrosivity test on a bunch of GL5s. Most of them pass just fine. I believe the GL5 spec isn't required to pass that test. Doesn't mean it won't, doesn't mean the manufacturer didn't do it, just that it isn't in the spec. ________ Vaporizer Review Last edited by atblis; 08-12-2011 at 01:07 AM.

02-12-2008, 06:31 AM	#6 (permalink)
atblis Registered User Join Date: May 2005 Member # 46937 Posts: 2,362	Yeah If you trackdown the Amsoil white paper on gear oils, they actually run the copper corrosivity test on a bunch of GL5s. Most of them pass just fine. I believe the GL5 spec isn't required to pass that test. Doesn't mean it won't, doesn't mean the manufacturer didn't do it, just that it isn't in the spec. I wouldn't rely on the MT-1 spec to tell you anything. In fact, it is intended for transmissions that are non synchronized. I can't find the tests it has to pass for the MT-1 spec so... A GL4 is what you want. ________ LIVE SEX Last edited by atblis; 08-12-2011 at 01:07 AM.

02-12-2008, 03:03 PM	#9 (permalink)
rockrknockr Registered User Join Date: Apr 2007 Member # 90393 Location: tucson Posts: 1,478	i don't see how the GL-5 could "eat" synchros in a week even the whole theory about it causing damage to synchros is hard for me to fathom but WTF do i know. i can say though that my AX15 works so much better with pennzoil synchromesh instead of the GL-5 75-90 shit. i might attribute to the pennzoil seeming a bit lighter weight than 75-90 even though i read it to be 80w. can't believe everything you read/hear Last edited by rockrknockr; 02-12-2008 at 03:05 PM.

02-12-2008, 05:02 PM	#10 (permalink)
atblis Registered User Join Date: May 2005 Member # 46937 Posts: 2,362	Well What brand of GL5 were you running? It varies. I've heard rumours of failures within maybe 5-10 k miles. Not weeks though. It appears that most GL5s are fine for brass synchros. That's probably what makes this whole thing so confusing. ________ ROLL A JOINT Last edited by atblis; 08-12-2011 at 01:07 AM.

02-11-2008, 04:13 PM	#2 (permalink)
jeffy Registered User Join Date: Sep 2001 Member # 7102 Location: SF East Bay Posts: 132	Well, if you still have the bottles you'll want to check and see if the GL-5 has the MT-1 designation or not. GL-5/MT-1 is syncro friendly and was reformulated soon after the whole GL-5 issue came up. Otherwise, it's hard to say how fast your syncro's will be damaged. You'll have to drain it and check for gold.

02-11-2008, 04:57 PM	#3 (permalink)
praetorian Wheeler Join Date: Dec 2007 Member # 105526 Location: La Mirada, CA Posts: 137	Now when you say, MT-1 is syncro friendly does that mean brass/bronze syncros, like in the AX-15>

02-11-2008, 05:04 PM	#4 (permalink)
jeffy Registered User Join Date: Sep 2001 Member # 7102 Location: SF East Bay Posts: 132	Yes, MT-1 designation means it's safe with yellow metals like copper and brass, ie. syncros.

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