GL-1 Gear Oil Alternative

I got SAE 50 motor oil from NAPA to put in mine.

paulfarber said:

No one has come up with anything remotely credible to change my mind. If your tranny blowed up because of GL-5/MT-1 please post!

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The simplest bit of information that should sway you if anything will is that Spicer, the maker of the transmission, says not to use oils with EP additives in their transmissions. GL5/MT1 is full of EP additives.

Spicer specifically recommends using SAE50 motor oil. SAE50 is the same viscosity as SAE90 gear oil. If you want something a little thinner, use SAE30, or SAE40.

-Chuck

Rockwell, the manufacturer of your T136-21 transfer case states 80w or 90w GL-1 or....

30w, 40w or 50w CD spec oil (diesel motor oil).

Attached is the page from the Rockwell manual.

mikew said:

Rockwell, the manufacturer of your T136-21 transfer case states 80w or 90w GL-1 or....

30w, 40w or 50w CD spec oil (diesel motor oil).

Attached is the page from the Rockwell manual.

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Do they recommend the same for the axles?

stumps said:

The simplest bit of information that should sway you if anything will is that Spicer, the maker of the transmission, says not to use oils with EP additives in their transmissions. GL5/MT1 is full of EP additives.

Spicer specifically recommends using SAE50 motor oil. SAE50 is the same viscosity as SAE90 gear oil. If you want something a little thinner, use SAE30, or SAE40.

-Chuck

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SAE 50 is a Viscosity Grade. Tells you nothing of what IN the oil, only how well it will flow at TESTED temps.

So you are happy to use SAE 50 maple syrup?

API is what you need to look at. THIS IS WHATS IN THE OIL. The pdf says API CD, CE, SF and SG are acceptable.

For Diesel Specs:

[SIZE=+1]CE[/SIZE] [SIZE=+1]Obsolete[/SIZE][FONT=Arial,Helvetica][SIZE=-1]Introduced in 1987. For high-speed, four-stroke, naturally aspirated and turbocharged engines. Can be used in place of CC and CD oils.[/SIZE][/FONT] [SIZE=+1]CD-II[/SIZE][SIZE=+1]Obsolete[/SIZE][FONT=Arial,Helvetica][SIZE=-1]Introduced in 1987. For two-stroke-cycle engines.[/SIZE][/FONT] [SIZE=+1]CD[/SIZE] [SIZE=+1]Obsolete[/SIZE][FONT=Arial,Helvetica][SIZE=-1]Introduced in 1955. For certain naturally aspirated and turbocharged engines.[/SIZE][/FONT]
Ops, CD and CE are not even current standards (read that they are no longer tested against any valid standards). Could be cow pee in that bottle as far as API is concerned.

Just to be through:

[SIZE=+1]SG[/SIZE][SIZE=+1]Obsolete[/SIZE][FONT=Arial,Helvetica][SIZE=-1]For 1993 and older engines.[/SIZE][/FONT] [SIZE=+1]SF[/SIZE][SIZE=+1]Obsolete[/SIZE][FONT=Arial,Helvetica][SIZE=-1]For 1988 and older engines.[/SIZE][/FONT]
What does API say bout current standards?

"For diesel engines, the latest category usually - but not always - includes the performance properties of an earlier category. "

Basically the new oils have continued to reduce the SULFUR content for emissions.

BTW, EP oils have sulfur as a wear reducing component. But since gearboxes do not see the same chemicals (heat, blow by, condensation) you can have a lot of sulfer/ phosphorus in them for wear protection, but not encounter any of the bad chemical reactions of sulfur at higher temps, in the presence of water etc.

I haven't seen a ton of transfer cases, but I cannot imagine what EP additives are going to harm. I used GL-5/MT-1 in every driveline component... diffs, tranny, transfer... nothing has rotted out in over 5 years on the jeep and 3 in the CCKW.

Also, what odd is FOOTNOTE 4: "Do not use Multi-viscosity GL-5 gear oil, axle lube. Is the prohibition on the multi viscosity rating or the GL-5 spec?

Going by the LO on this site:

MIL-L-2105 is the oil for the diffs, tranny and transfer.

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.

[FONT=Arial, Arial, Helvetica] +GL-5[/FONT]
[FONT=Arial, Arial, Helvetica] [/FONT] [FONT=Arial, Arial, Helvetica] This designation denotes lubricants intended for gears, particularly hypoid gears, in axles operating under various combinations of high-speed, low-speed, high-torque, and shock-load conditions. Lubricants qualified under U.S. Military Specification MIL-L-2105E (formerly MIL-L-2105D) satisfy the requirements of the API GL-5 service designation. Performance test details are in ASTM Publication STP-512A, "Laboratory Performance Tests for Automotive Gear Lubricants Intended for API GL-5 Service."[/FONT]

2105E supersedes A,B,C,D. So unless they made a MIL-SPEC oil that is COMPLETELY incompatible with all previous oils, and release Tm changes for all previous assemblies to NOT use the latest 2105X standard, GL-5 IS GOOD TO GO.

Yeah, now someone comes up with some 10-20 year old scrap of paper that say X, Y, or Z. And round and round we go.

paulfarber said:

SAE 50 is a Viscosity Grade. Tells you nothing of what IN the oil, only how well it will flow at TESTED temps.

So you are happy to use SAE 50 maple syrup?

API is what you need to look at. THIS IS WHATS IN THE OIL. The pdf says API CD, CE, SF and SG are acceptable.

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Let's not get too anal here Paul, I said SAE50 motor oil, not SAE50 maple syrup.

I haven't seen a ton of transfer cases, but I cannot imagine what EP additives are going to harm. I used GL-5/MT-1 in every driveline component... diffs, tranny, transfer... nothing has rotted out in over 5 years on the jeep and 3 in the CCKW.

Also, what odd is FOOTNOTE 4: "Do not use Multi-viscosity GL-5 gear oil, axle lube. Is the prohibition on the multi viscosity rating or the GL-5 spec?

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The synchronizers are clutches, and rely on the oil making them have a certain amount of friction, for their operation. If you use an oil that is too slippery, the synchronizers will not spin up the gear clusters, and the transmission will grunk. The converse can also have an effect, and make it very hard to force the shifter into gear.

The point is Rockwell tried GL-5 multi-vis gear oil, and said it isn't acceptable for their transfer cases. Spicer has said the same thing for their transmissions. Why don't you believe them?

The government, in specifying a multi-vis GL5 oil for the deuce did so to eliminate some complexity in their supply system. They preferred carrying only 85W90 GL5 oil, over carrying SAE50 motor oil, SAE 90 GL1/MT1, SAE 85W90 GL5, ... They clearly made the decision against the advice of the makers of the transmission, and transfer case. Good enough won out over great. We don't have that same inventory problem. We can afford a little variety in the supplies we stock.... Well, I can anyway.

-Chuck

Where are you getting this 'no GL-5' from?

The manufacturer or the TM?

The current oil spec is GL-5 compatible.

Wet clutch != snychro. If the transmission is not syncing you can always double clutch.

A synchro is never meant to fully engage.

All I am seeing is scraps of paper with wandering bits of trivia. The LO, the TM and the MILSPEC for current GOs is GL-5 compatible.

Why do people think that there is some huge incompatibility? If the owner and operator of the country's largest fleet of vehicles wants a lube that is NOT GL-5 rated, I'm sure they'll get it. But the current standard IS GL-5 compatible.

Casual observation shows that the government has been moving steadily to simplify its supply chain for years. At one point, there were multiple fuels (mogas, diesel, jp), multiple engine oils, multiple gear oils, multiple greases, and multiple brake fluids. Now there is one diesel type fuel (jp), one engine oil(15W40), one gear oil (85W90 GL-5), one grease (GAA), and one brake fluid(BFS).

In settling on one of each class of fluid, compromises were made. Simplifying supplies was more important than minor long term adverse effects.

The no multi-viscosity, and no EP for transfer cases, and transmissions comes directly from Spicer, and Rockwell. The offending documents have been posted on this list.

The government chose to ignore the manufacturers of these old transmissions, and transfer cases and specified a multi-viscosity EP gear oil to fill everything with gears. They did so when the writing was already on the wall that they were getting rid of these trucks soon. What do they care about longevity in a vehicle that typically only travels 10 or 15,000 miles over its lifetime, and was scheduled to be surplussed?

-Chuck

The Spicer page posted above says not to use GL-5. The question is why and what changes has GL-5 gone through since those tests. I am not formally trained about oils and lubrication but here are some basic observations from studying in my own persuit of what to put in my deuce.

GL-5 used to be harmful to the brass in the syncros. Now it is yellow metal safe. Are you not supposed to use it because at the time of the testing it would eat the brass or because does not lubricate properly? I don't know the answer but it seems some are using GL-5 without trouble. I have some GL-5 and I might put it in the tranny and trans case for a year and see what happens. I can't imagine it doing that much harm in a year and if the gears do go out, there must have been something else wrong.

I can see the standpoint that the EP additives might decrease friction between the "clutches" in the syncros. I will see how the tranny shifts and in a year I'll drain the tranny and trans case and see if I get anything funky coming out. Maybe even send an oil sample in for analysys. What we really need in this quest for oil truth is real data. No offense to the guys who post their personal experiences, experience is invaluable. However, it is time for some real numbers and scientific style tests.

I don't think the Army is dumb enough to put incompatible oil in the drive train, end of life or not. Is there SIGNIFICANT difference in the rebuilt M35s in use NOW vs the rebuilt M35s showing up on GL? Other than the A3 and auto trans, I don't believe so.

I agree that way back when GL-5 did have a yellow metal issue. But the MT-1 spec clears that up, and even then the sulfur had to get hot (250F+ hot) before the chemical reaction to make the acid occurred. But like not fully loading an M-16 magazine to prevent misfeeds, that to is ancient history and only comes up when the uninformed bring it up.

I have GL-5 in my jeep now for over 3 years. Tranny and transfer. There are plenty of brass bushings and synchro's and they are working fine.

If you want to be an 'oil snob' and 'only run what the TM says' then OK, great, have at it... but don't say that GL-5 is wrong, because that's what in use NOW as GO (as per the spec posted above).

paulfarber said:

I don't think the Army is dumb enough to put incompatible oil in the drive train, end of life or not. Is there SIGNIFICANT difference in the rebuilt M35s in use NOW vs the rebuilt M35s showing up on GL? Other than the A3 and auto trans, I don't believe so.

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They put the oil canisters upside down and above the oil sump level against Hercules's recommendation, they used bobble head valves on gear boxes, transmissions, and differentials, without providing a means for equalizing pressure after cool down. The Army does lots of things that are dumb in the name of expedience. They have different issues than the manufacturers do, so they often go against manufacturer's recommendations. GL-5 is one of those instances.

I agree that way back when GL-5 did have a yellow metal issue. But the MT-1 spec clears that up, and even then the sulfur had to get hot (250F+ hot) before the chemical reaction to make the acid occurred. But like not fully loading an M-16 magazine to prevent misfeeds, that to is ancient history and only comes up when the uninformed bring it up.

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The Army says nothing about GL-5 in its lubrication order for the deuce. They talk of using GO which meets MIL-L-2105. GL-5 is a civilian designation, which means nothing to the Army.

When you look at a drum of lubricating oil, and find an alphabet soup of meets this, or that, letters listed, what you are looking at is what the oil blender tried to achieve, when creating the additive package they blended into the base oil. If the blender says that it meets GL-1, GL-4, GL-5, MT-1, CATxxx, DDyyy, ... They are telling you that they tested the oil, and it passed the GLI (and other parties) tests for each of those categories. They are not telling you that it will be the optimal oil for your transmission, nor are they telling you that it won't destroy your transmission. Look long and hard for any performance guarantee. I don't think you will find it.

I have GL-5 in my jeep now for over 3 years. Tranny and transfer. There are plenty of brass bushings and synchro's and they are working fine.

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Great! If only I could trust that your idea of working fine matched mine. Your experience in that jeep is limited to a single brand of GL-5 blended oil.... over whatever temperature range, and operating conditions, you have decided is fine with you.

How do you know that your transmission would not perform much better with the oil the manufacturer recommends? ... Rather than with one they specifically recommend against? They did some extensive testing that none of us could ever hope to achieve.

How do you know that after 3 years of your testing, you are going to see years 15 through 25? Thus far, I have never given up on a car, truck, or tractor, that I haven't owned for at least 20 years.

If you want to be an 'oil snob' and 'only run what the TM says' then OK, great, have at it... but don't say that GL-5 is wrong, because that's what in use NOW as GO (as per the spec posted above).

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I don't believe I have said anything about the oil the TM says is OK. I have been talking of the oil the MANUFACTURER recommends vs the oil the MANUFACTURER says not to use.

-Chuck

I think I'll keep using GL1 from napa.

They talk of using GO which meets MIL-L-2105. GL-5 is a civilian designation, which means nothing to the Army.

Um.. read the spec sheet. There is a list of documentation used for reference on how to perform the test, what the results should be etc. They are the same as GL-5. If MIL-L-2105 meets the API specs for GL-5, its GL-5. Stop grabbing random scraps of paper that only serve to lead you down a path that goes nowhere. Also, GL-5 is THE specification.. not just a civvy one.

They put the oil canisters upside down and above the oil sump level against Hercules's recommendation, they used bobble head valves on gear boxes, transmissions, and differentials, without providing a means for equalizing pressure after cool down. The Army does lots of things that are dumb in the name of expedience. They have different issues than the manufacturers do, so they often go against manufacturer's recommendations. GL-5 is one of those instances.

So what? More random scraps of paper. The manufacturer is ultimately responsible for parts and meeting lifetime expectancy of the parts under the costs and terms of the contract. They didn't complain to much as the Army got what it wanted, and the manufacturer had to support it. I'm sure that the manufacturer wants a lot of things to avoid having to cover failures and increase profit.

If the blender says that it meets GL-1, GL-4, GL-5, MT-1, CATxxx, DDyyy, ... They are telling you that they tested the oil, and it passed the GLI (and other parties) tests for each of those categories.

GL-1 does not exist as a standard, CAT and DD can make up whatever they want. API is a standards setting body, and if they make obsolete or supersede a standard then OFFICIALLY its a done deal. NAPA can put GL-1 on a can of cow pee and API will not care (UNLESS they make a claim that it meets/exceeded an API classification). CAT can say their oil standard included 1 pound of Tennessee river mud... who cares.. its not a standard set by a recoginzed body, NOR CAN THEY VOID A WARANTEE FOR NOT USING RECOMMENDED OIL. This has been hashed out in the 70's when car manufacturers were playing the 'you must use our oil or we will not fix anything' crap. You are still doing nothing but grabbing at random bits of trivia.

This is all common knowledge.

Again, GL-5 is fine. No one is having gears rot out, nor blowing up drivelines because they are using GL-5 WHICH IS WHATS IN THE DEUCE IF IT WAS SERVICED BY THE ARMY IN THE LAST 10 YEARS!!!!!!!!!!!!!!!!!!!!!

All the GL-1 guys either cannot, or will not read the lube order (its free on this site) and the CURRENT (since, oh, the mid 90s?) HAS BEEN A GL-5 LUBE OIL.

Show me a CURRENT lube order that stated that GL-1 is the proper lube and then you have my attention. Till then please keep your random scraps of paper in a nice neat folder... maybe use them as tinder to start a fire, as they are not of any other use.

For the WIN:

Para 6:

6.1 Intended Use: The gear lubricants covered by this specification meet American Petroleum Institute (API) Service Classification GL-5 and are intended for .......

http://www.everyspec.com/MIL-SPECS/MIL+SPECS+(MIL-L)/download.php?spec=MIL-L-2105D.00002029.pdf

THERE YOU HAVE IT. The lube called out BY THE LUBE ORDER for them M35 is MIL-L-2105D. The MIL SPEC notes CLEARLY STATE that its a GL-5 oil.

Case closed.

buying a spare transmission, just in case

so Paul,
It will be ok to use my GL5/ MT1 bottles of 80-90w from Wallyworld in my deuce transmission?

I am running GL-5 MT1 in my transmission, transfer, axles, and winch. That what I got from SA White in Marietta. So.......leave it....change it.

I'm still going to stick with GL-1 as long as I can still get it. I don't know if it's got cow pee or TN river mud in it but my trans seems to like it.

m16ty said:

I'm still going to stick with GL-1 as long as I can still get it. I don't know if it's got cow pee or TN river mud in it but my trans seems to like it.

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Whats kinda funny is that if you got the truck from GL, or any truck released from active inventory, it had GL-5 lube in it. So, since about 1993 IIRC its had GL-5 in it, then you read an outdated TM (again, I cannot find a LO on this site that specifies a GL-1 rated oil) and think that somehow the new maintenance procedures/specs are going to rot out a drive line.

I would think that 17 years of GL-5 in an M35 would be sufficient time to rot out *something* if there was an issue with it.

I am not disagreeing with the use of GL-1, any oil is better than no oil.... but I find it irritating that some people say the GL-5 is the *WRONG* spec oil. That needs to be addressed and clarified.

Its akin to the 'knuckle lube' guys get all uppity about in jeeps. If you want to hear old wives tales, get two jeep owners together and ask one about knuckle lube.

mcmullag said:

so Paul,
It will be ok to use my GL5/ MT1 bottles of 80-90w from Wallyworld in my deuce transmission?

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That's what the LO calls for. I use the 'SuperTech' brand (Wally Worlds house brand) and its good stuff. I also use the SuperTech oil filters for my 'zuki and the 'SuperTech' oil for all my cars.

As long as it has the appropriate API logo/designator then they are guaranteeing meeting the API spec.

You do have to be careful, some really, really off brands have a circle logo, but its not the API one. Generally recycled oils have them... look for them at the dollar store.