Gear Oil API GL-5 vs GL-4


Information and questions on GL1100 Goldwings (1980-1983)
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tcoholmes
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Motorcycle: 1982 GL1100 aspencade Goldwing
1979 CB 750K
1986 Yamaha XT 350
2005 KTM EXC 525

Gear Oil API GL-5 vs GL-4

Postby tcoholmes » Mon May 07, 2012 10:39 pm



For my 82 GL-1100A I just purchased gear oil type API GL-4 (Pennzoil Synthetic SAE 75W-90). The manual calls for API GL-5. Is there a significant difference between the two (GL-4 vs GL-5)? They are both designed for hypoid gears systems but the GL-5 is additionally designed for high torque conditions.
Thanks for any input.



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cbx4evr
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Re: Gear Oil API GL-5 vs GL-4

Postby cbx4evr » Tue May 08, 2012 9:48 am

I'm actually surprised that you found GL-4. It isn;t that common.

Personally I would get the Gl-5 as specified by the manual.


GL-4; Specified for hypoid gear service under severe service but without shock loading. This classification is essentially obsolete but is still specified by some manual transmission/transaxle manufacturers. Implies an EP/AW additive package that contains 30% to 50% less S-P additives than the GL-5 service classification. Some Marine Gear Lubes fall into this classification, especially the full Synthetic Marine Gear lubes and specialty blenders MT lubes that use high levels of esters.

GL-5; Specified for hypoid gear service but with shock loads and severe service operation. Usually meets Mil-L-2105D and in most cases, is the multipurpose automotive gear oil. Most 75W90 to 75W140 grades meet the GL-5 classification. This grade has a high level of Extreme-Pressure additives that could be mildly corrosive to nonferrous parts, such as brass, bronze and aluminum parts. Most of the modern GL-5 lubes contain metal deactivators that prevents attacks by the extreme-pressure additives. In addition to EP additives, these lubes contain rust inhibitors, defoamants, friction modifiers, thickeners, and Viscosity Index Improvers.
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tcoholmes
Posts: 4
Joined: Sat Aug 13, 2011 8:18 pm
Location: Calgary, Alberta, Canada
Motorcycle: 1982 GL1100 aspencade Goldwing
1979 CB 750K
1986 Yamaha XT 350
2005 KTM EXC 525

Re: Gear Oil API GL-5 vs GL-4

Postby tcoholmes » Tue May 08, 2012 9:33 pm

Thanks cbx4evr
great info


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