12-09-2009, 04:35 PM
|
#60 (permalink)
|
|
A True Z Fanatic
Join Date: Sep 2009
Location: Gold Coast CT
Posts: 10,599
Drives: 2019 Corvette G.S.
Rep Power: 43
|
[QUOTE=Modshack;314874]Apparently it''s not that simple.....
Seems it has a lot to do with the additive package. More info from Bobstheoilguy:
Quote:
I cannot vouch for any lube except ours. In the past, manufactures speced GL4 because of the lower levels of the Sulfur-Phosphorous (S-P) additive package. The lower levels guaranteed less interaction (such as staining and corrosive pitting) with copper alloys such as brass and bronze.
However, and since about 2000, most additive packages now contain "inactive" sulfur which is mediated by metal deactivators and which do not allow the sulfur to interact with the copper-alloy metals, but still allows the S-P additive to protect the gear teeth and bearings.
The problem with most OTS GL5 lubes in MT's is their viscoity and friction modifiers. While the OTS GL5 gear lubes are great for differentials, they do not possess the correct viscosity or friction modification for smooth cold weather shifting.
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.[/unquote]
obviously some usage tests and experimentaion are called for. I'll be the guinea pig.
|
Taking one for the Team  . In for updates
__________________
SOLD MY Z MARCH 2018 - another Core OG moves on - new ride 2019 Z Corvette Grand Sport - no mods necessary but already have eyes on HFC and intakes LOL IT NEVER ENDS.
|
|
|