GL-1 vs GL-5/MT-1

[sprucemt]

I'm sure this in the archive somewhere, but here it is fresh.

What’s the difference?

The performance requirements for automotive gear lubricants depend on their intended use.

API Category GL-1 (inactive*) designates the type of service characteristic of manual transmissions operating under such mild conditions of low unit pressures and minimum sliding velocities, that untreated oil may be used satisfactorily. Oxidation and rust inhibitors, defoamers and pour depressants may be used to improve the characteristics of lubricants intended for this service. Friction modifiers and extreme pressure additives shall not be used.
API Category GL-2 (inactive*) designates the type of service characteristic of automotive type worm-gear axles operating under such conditions of load, temperature and sliding velocities, that lubricants satisfactory for API GL-1 service will not suffice.
API Category GL-3 (inactive*) designates the type of service characteristic of manual transmissions and spiral-bevel axles operating under mild to moderate to severe conditions of speed and load. These service conditions require a lubricant having load-carrying capacities greater than those that will satisfy APL GL-1 service, but below the requirements of lubricants satisfying the API GL-4 service.
API Category GL-4 designates the type of service characteristic of spiral-bevel and hypoid gears in automotive axles operated under moderate speeds and loads. These oils may be used in selected manual transmission and transaxle applications.
API Category GL-5 designates the type of service characteristic of gears, particularly hypoids in automotive axles under high-speed and/or low-speed, high-torque conditions. Lubricants qualified under U.S. Military specification MIL-L-2105D (formerly MIL-L-2015C), MIL-PRF-2105E and SAE J2360 satisfy the requirements of the API GL-5 service designation.
API Category GL-6 (inactive*) designates the type of service characteristic of gears designed with a very high pinion offset. Such designs typically require (gear) score protection in excess of that provided by API GL-5 gear oils. The original API GL-6 test equipment is obsolete.
API Category MT-1 designates lubricants intended for non-synchronized manual transmissions used in buses and heavy-duty trucks. Lubricants meeting API MT-1 provide protection against the combination of thermal degradation, component wear, and oil seal deterioration which is not provided by lubricants meeting only the requirements of API GL-4 and API GL-5.
MIL-PRF-2105E this specification released in 1995 combines the performance requirements of its predecessor (MIL-L-2105D) and API MT-1. MIL-PRF-2105E maintains all existing chemical/physical requirements, stationary axle test requirements, field test requirements and data review by the Lubricants Review Institute that were required under MIL-L-2105D. It also adds the stringent oil seal compatibility and thermal durability test requirements under API MT-1. MIL-PRF-2105E has been re-written as SAE Standard J2360.
SAE J2360 standard is a new global quality standard that defines a level of performance equivalent to that defined by MIL-PRF-2105E, a U.S. military standard for approval that was not available to oil blenders in all parts of the world. It includes all of the most recent axle and transmission testing requirements identified in API GL-5, API MT-1, and MIL-PRF-2105E including the need to demonstrate proof-of-performance through rigorous field testing.
* API Categories GL-1, GL-2, GL-3 and GL-6 were declared inactive by SAE Technical Committee 3 in 1995, even though oils may be marketed with these designations. Similarly, ASTM does not plan to maintain the performance tests associated with these categories, as in a number of cases these tests can no longer be run because parts or test installations are not available.

For the rest of the article

http://www.lubrizol.com/products/automotive-gear-oil/GL5.asp

 

[acetomatoco]

All these trucks designed in 1949 were intended for GL1...and most old farm tractor shops still stock 5 gallon pails of it... Use of the newer variations with "brass" additives and other hooplah are just wasted money... However the new yuppie diehards can spend their easy gotten moolah for the higher GL#s without breaking their toys. Comments from a GL1 fan...

 

[sprucemt]

Purist's

And to think this started with a fleeting thought to stock and sell GL-1 on my website.

Any snow yet, way up north there Ross?

 

[OPCOM]

RE: Purist

GL-5/MT-1 retains its performance better than GL-1 when it is hot. For the extra few dollars, I'll spend my hard earned money on it. I don't know of any yuppies with MVs around these parts. I suspect they are all up north with the yankees in places like New York City.

 

[OD_Coyote]

Re: RE: Purist

GL-5/MT-1 retains its performance better than GL-1 when it is hot. For the extra few dollars, I'll spend my hard earned money on it.

Plus my other vehicles use GL5, so I do not have to keep (2) types of GO stashed in my already stuffed shop.

 

[HeadWizard]

Thanks for the data on the different type of lubes.

I'm sure some of us will stick to the old school, old lube technology that lasts as long as it lasts, might cost a little less money and was engineered when slide rules were cutting edge technology and cars lasted 40k miles if you got lucky before the engines expired due to poor lubrication....

...and some of us will embrace progressive thought and new technology that includes additives and synthetic ingredients, might cost a little more in the bucket (but less when labor costs of extended drain intervals is considered), that is being engineered in the era of supercomputers and nano-technology where cars (and engines) routinely last 150k - 200k miles due to superior lubrication.

I would appear that all the redneck, yuppie, northerner, old fart, southerner, politician, low life, cheese-head, left-coaster, blue state, Hoosier, red state, hillbilly, nerd, Cajun, chowder-head, blue collar, Hokie, white collar, easterner, veteran, NASCAR fan, alien, lawyer, government worker, metro sexual, plowboy, criminal, moron, stud, Mensa member, homeless, Buckeye, teacher, patriot, homeboy, canuck, flatlander, dink, beltway bandit, Confederate, boomer, Gen-X'r, hippie, commie, jock, freak, Parrotthead, Deadhead, geek, beach bum, cowboy, student, retiree, rocker, and Yankee MV hobbyists have a lube choice to make?

I love the USA! Free speech and the freedom to choose your own slippery slimy lube!

 

[alphadeltaromeo]

On hot Georgia summer days, would GL5 be better in my hair or GL1...?

 

[acetomatoco]

Depends on whether you have brass knuckles or not...I prefer GL1 for the smell...of course I used to wash all my parts in leaded gasoline before the gummint took it away and it may have addlled my judgement...but my parts were nice and clean..

 

[doghead]

I would appear that all the redneck, yuppie, northerner, old fart, southerner, politician, low life, cheese-head, left-coaster, blue state, Hoosier, red state, hillbilly, nerd, Cajun, chowder-head, blue collar, Hokie, white collar, easterner, veteran, NASCAR fan, alien, lawyer, government worker, metro sexual, plowboy, criminal, moron, stud, Mensa member, homeless, Buckeye, teacher, patriot, homeboy, canuck, flatlander, dink, beltway bandit, Confederate, boomer, Gen-X'r, hippie, commie, jock, freak, Parrotthead, Deadhead, geek, beach bum, cowboy, student, retiree, rocker, and Yankee MV hobbyists have a lube choice to make?

Dang! I resemble several of these names but, I'm NOT A YUPPIE! (and I have the GL1 can in the garage to prove it!)

Ps, Sorry Don, Way off topic here!