Not long after Shell bought out Pennzoil-Quaker State, they discontinued all of their commercial-industrial lines, and several low volume automotive products. The GL-4s were one of those.
75W-90 GL-4 (brass synchros) Fluid Options
- Thread starter badtlc
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Toyota, Mazda, and various automakers state GL4 or GL5. None state whether to avoid LS additives or not. None mention whether you need a certain chemistry or not. When it is a blanket broad automaker recommendation, I would purposely AVOID LS and GL5 gear oils when GL4's are available and an option. As long as Redline/Amsoil are around, use the GL4!
Would I use the XDM? only if no other GL4 was readily available. Availability of a GL5 non-LS Mack GOJ+ 75w90 is everywhere and have yet to see them NOT work in a manual transmission from Toyota, Mazda, Hyundai/Kia, Subaru, Nissan, Mitsubishi....
Delo Syn-Gear XDM meet and exceed the requirements of API Service Categories GL-4, GL-5 and MT-1.
Is it the best choice? That is for the owner to decide. But, XDM does fall under the non-LS GL-5's and CAN be used whether I recommend or not when the automaker states a GL5 can be used.
We've used GL5's and GL4 marine gear oils in the shop since the 1980's and NEVER had one come back with synchro problems. Suddenly, every manual owner is either too incompetent to drive a manual, or too lazy to change the gear oil out regularly, has problems with so-called chemistry, synchros, or certain fluids. I'd also guess that maybe the LS additives weren't standard ages ago like now. Or, maybe owners weren't limpwristed snowflakes back then and were man enough shift a transmission with straight 140 grade when its 0°F outside.
Enjoy the OTR EP fluid in your transmission because your automaker allows a GL5 in the owners manual.
BTW, no need to turn this thread into a classroom. Nobody cares about the chemistry of the fluids or how to blend them. Save it for your students. And, yes, some of us know but don't brag about it constantly. The debate and requirements of a spec is irrelevant. Oh, and yes, I under what is required for the GL4/GL5/MT1 specs. Big fooking deal. Do you know how to make a syncro or a transmission gear? have you ever made one? or how to tear a manual transmission apart, address shortcomings on prototypes, and put them back together updated for said shortcomings? Yes, its all irrelevant to the OP's thread.
And again, do not use Pennzoil Synchromesh or the equivalent Valvoline MT fluids. The OP requires a 75w90 but didn't state year/make/model or owners manual requirements. The Pennzoil 75w90GL4 was still available at distributor but not sure anyone wants to buy a pail. And the Valvoline 75w90 GL4 was VIOC only, and anyone near a valvoline instant oil change quicklube can visit them to see if they still have it.... just be careful as most VIOC techs won't know the difference between the 75w90 and the GM synchromesh versions of the Valvoline MT fluids.
My only recommendation is to change the gear oil out more frequently. I don't ever use gear oil for more than 30k miles 3-4 years.
And, for the OP needing to verify a working salvaged transmission prior to using Redline...., my previous recommendations stand. Yes, the 40 to 50 grade motor oils, the GL4 90 grade marine oils, the GL5 non-LS gear oils are great to verify function, transmission sealing, and for salvage yard transmission debris cleaning. The only way to install a recycled gearbox, imo, is to rinse it once, prior to sending it back to the customer. Nothing worse than their fancy Amsoil/Redline fluid leaking out in their driveway, or the transmission is worn out an whines or doesn't shift well enough. Someone preaching, and not wrenching, wouldn't understand this.
Would I use the XDM? only if no other GL4 was readily available. Availability of a GL5 non-LS Mack GOJ+ 75w90 is everywhere and have yet to see them NOT work in a manual transmission from Toyota, Mazda, Hyundai/Kia, Subaru, Nissan, Mitsubishi....
Delo Syn-Gear XDM meet and exceed the requirements of API Service Categories GL-4, GL-5 and MT-1.
Is it the best choice? That is for the owner to decide. But, XDM does fall under the non-LS GL-5's and CAN be used whether I recommend or not when the automaker states a GL5 can be used.
We've used GL5's and GL4 marine gear oils in the shop since the 1980's and NEVER had one come back with synchro problems. Suddenly, every manual owner is either too incompetent to drive a manual, or too lazy to change the gear oil out regularly, has problems with so-called chemistry, synchros, or certain fluids. I'd also guess that maybe the LS additives weren't standard ages ago like now. Or, maybe owners weren't limpwristed snowflakes back then and were man enough shift a transmission with straight 140 grade when its 0°F outside.
Enjoy the OTR EP fluid in your transmission because your automaker allows a GL5 in the owners manual.
BTW, no need to turn this thread into a classroom. Nobody cares about the chemistry of the fluids or how to blend them. Save it for your students. And, yes, some of us know but don't brag about it constantly. The debate and requirements of a spec is irrelevant. Oh, and yes, I under what is required for the GL4/GL5/MT1 specs. Big fooking deal. Do you know how to make a syncro or a transmission gear? have you ever made one? or how to tear a manual transmission apart, address shortcomings on prototypes, and put them back together updated for said shortcomings? Yes, its all irrelevant to the OP's thread.
And again, do not use Pennzoil Synchromesh or the equivalent Valvoline MT fluids. The OP requires a 75w90 but didn't state year/make/model or owners manual requirements. The Pennzoil 75w90GL4 was still available at distributor but not sure anyone wants to buy a pail. And the Valvoline 75w90 GL4 was VIOC only, and anyone near a valvoline instant oil change quicklube can visit them to see if they still have it.... just be careful as most VIOC techs won't know the difference between the 75w90 and the GM synchromesh versions of the Valvoline MT fluids.
My only recommendation is to change the gear oil out more frequently. I don't ever use gear oil for more than 30k miles 3-4 years.
And, for the OP needing to verify a working salvaged transmission prior to using Redline...., my previous recommendations stand. Yes, the 40 to 50 grade motor oils, the GL4 90 grade marine oils, the GL5 non-LS gear oils are great to verify function, transmission sealing, and for salvage yard transmission debris cleaning. The only way to install a recycled gearbox, imo, is to rinse it once, prior to sending it back to the customer. Nothing worse than their fancy Amsoil/Redline fluid leaking out in their driveway, or the transmission is worn out an whines or doesn't shift well enough. Someone preaching, and not wrenching, wouldn't understand this.
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This seems like the kind of mentality that leaves you with metal flakes in your drain pan every 30k.
MolaKule
Staff member
Yep, I talk to my Oronite reps about once a month.
I said the OLOA 9750 contained a "compound." This means a mixture of various chemistry.
Most Borate esters used in engine oils and gear oil are of the class of S-(Di-n-octyl-borate)-ethyl-N, N0 -dibenzyldithiocarbamate (DOB-EBzDTC)
and S-(Di-n-octyl-borate)-ethyl-N,N0 -di-nethyldithiocarbamate (DOB-EEDTC), and similar synthesized borates.
One can use the OLOA 9151 as single EP additive but if one uses a commercial Primary SP additive then OLOA 9750 can be added as a secondary EP additive. to "tune" the overall formulation for a specific application.
There is a constant need for education regarding these gear fluids since there are recurring, multiple misunderstandings of a manual transmission fluid's interaction with the internal mechanics of a Manual Transmission.
The rest of your comments are mostly irrelevant fodder that prove nothing, and believe it or not, even you can benefit from some additional technical education.
I have torn down and rebuilt automatic transmissions, Muncie manual's, Nissan and Datsun manual's and a few others.
And for fun, I used to rebuild Suburban drive trains for racing.
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That's what I'm running in our '09 Mazda 5. Bought it from a local NAPA.
I ran into this with my 2000 VW GTI manual and now my 1990 Toyota 4x4 pickup as well both require a GL4. I don’t use the gl5 that states also Gl4 compatible and find the amsoil Gl4 easiest for me to get. Great stuff for sure. Actually need to order some now.
Not to be even more difficult, but it isn’t GL5 that also states GL4 any more than GL4 that also states GL5. Oils say meets or exceeds GL4, GL5 is just that. There is no second position for either grade. As far as I know. If it says what my manual says, then it’s ok. Then I go do something else. ⛷
Whoa, that's weird! Usually we miss out on all the good stuff that's available in the States.Napa sells that Pennzoil 75w90 GL4 in Canada, but not the US
MolaKule
Staff member
GL-4, GL-5 are not "Grades," they are wear protection ratings for gearing and bearings in gear trains.Not to be even more difficult, but it isn’t GL5 that also states GL4 any more than GL4 that also states GL5. Oils say meets or exceeds GL4, GL5 is just that. There is no second position for either grade. As far as I know. If it says what my manual says, then it’s ok. Then I go do something else. ⛷
Grades describe a range or ranges of viscosity.
GL-4 is a wear protection rating primarily for light truck and passenger car manual transmissions because a.) of the lower torque loads encountered, b.) the type of internal gearing used. A major chemistry component in GL-4 fluids is the Anti-wear chemistry, usually a good dose of ZDDP. For MT's with synchronizers, special friction modifier chemistry is required.
What this means is not ALL GL-X fluids are designed to be used in manual transmissions because they do not contain the correct mix of chemistry.
This is why GM had Texaco develop the "Synchromesh" transmission fluid for their synchronized transmissions, an application-specific or "dedicated" fluid just for synchronized transmissions to improve shifting.
GL-5 covers highly loaded (Hypoid) differentials and OTR (MT-1) truck transmissions where high torque loads are encountered and use different gearing designs than do light truck and passenger manual transmissions. MT-1 transmissions may or may not be synchronized and usually contain all steel alloys. The anti-wear protective additive pack in GL-5 fluids contains Extreme Pressure chemistry, with the primary chemistry historically being Sulfur-Phosphorus additives.
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Except a Pennzoil 75w-90 GL-4 is still listed as currently available on their updated product website in the usa.
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To get the Pennzoil, you either buy a case or pail if your local distributor carries it. Good luck finding it was on a shelf and most dont need that volumr for a 2-3 qt manual transmission.
If the automaker states a GL5 can be used, whether optimal or not, who cares! Automakers make many recommendations that consumers follow blindly.
If the automaker states a GL5 can be used, whether optimal or not, who cares! Automakers make many recommendations that consumers follow blindly.
I think it is fine to call GL4, 5 grades, very broad meaning in that word. I would still call it grades. It is interesting, because on this site the word weight is used constantly for oil viscosities. There should be a lecture on that to the folks. GL4 or 5 is fine my friend for my Toyota, they say so, the oil bottle says so. As an end user that’s all I need to think about. Thanks.
Unfortunately, it isn't actually sold anywhere in the US
Napa carries it in Canada. I've seen a few listings of the PP GL4 on eBay, and from a couple obscure sites like evolubesupply (which also sells on eBay), but it just doesn't exist on the she;f of any US retail store.
The only 75w90 GL4 for sale in a US store is Liqui Moly from Napa, and even then, it might not actually be in-stock, so you have to order it, but it will arrive at the store in a day or two.
When it was my job to sell it, we were told it was being disco'd, and would be unavailable when current stocks were depleted. There was a Shell Spirax S2 GL-4 to replace it.
What's available to local distributors and distribution centers isn't necessarily the same as what can be had by large direct ship accounts. For years, the only place to get PQS products in a 5 quart package was Walmart, because they demanded one.
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Interesting, I've seen Shell Spirax gear oil products on the shelf in Europe, but not in the USA..Unfortunately, it isn't actually sold anywhere in the US
Napa carries it in Canada. I've seen a few listings of the PP GL4 on eBay, and from a couple obscure sites like evolubesupply (which also sells on eBay), but it just doesn't exist on the she;f of any US retail store.
The only 75w90 GL4 for sale in a US store is Liqui Moly from Napa, and even then, it might not actually be in-stock, so you have to order it, but it will arrive at the store in a day or two.
I know for VW they offer Spirax S3 G 80w GL-4 and Spirax S6 GXME 75w-90 GL-4 as well.
MolaKule
Staff member
No it's not fine to call a gear protection rating a Grade because it is incorrect.
The word "weight" is often used incorrectly but a Grade is the correct term for a range of viscosities and people get corrected and educated about it.
If you want to converse properly in the oil industry then you must use the correct terminology.
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A person coming here is not required to be licensed in oil industry jargon. English meaning of grade covers millions of subjects. As long as I said GL4 or 5 grade there is no reason to not be able to understand it in your terms. Viscosity I say grade too. What I can’t say is weight which is nonsense. I always think of tires and their “thread.” So what do you call GL4 when you don’t want a lot of words? I certainly will never write gear protection rating every time. Any suggestions on a word? Class? Type? Maybe it’s just Rating. Ok, GL4 rating, how’s that? Sounds pretty good to me. I mean in an oil experts place that calls oil grades by weights, give me a break calling something a grade versus rating. All said in good humor.
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English language is always changing. Acceptable usage of a term depends on the users and is always being adjusted. Its not like a definition in a dictionary has never been adjusted or new words never ever added to the English dictionary. BTW, can't stand how Aussies and Brits talk. Don't care for ebonics. And, definitely can't someone with their nose up and pole up in their... Bafflegab!
Funny how some additive/base oil suppliers we used call the gear oil GL "SERVICE DESIGNATIONS" a grade. So, in certain circles, its a service designations "GRADE" and along with the viscosity GRADE. And, slang term weight seems to be used by consumers. Doesn't make it wrong or right and again, who cares what you call it. The edjewcashun and Engrish doctorates can come along and argue here if they want.
So, who here walks into the auto part store asking where the service designation GL5 is located?
BTW, it annoys me when the word "anti-foam" or "antifoamers" are used to explain Si levels in motor oil, atf, gear oil..... in the UOA or VOA sections. Hate it. The refineries and blending plants I worked in called that part of your additive package a defoamer and another used inhibitor.. Maybe its just location dependent.
Gotta run. Going to pick up some GL5 grade gear oil for my car and some thick weight oil, both hopefully with enough antifoam, for my engine and gearbox
Or, maybe I should ask for GL5 level and 80w90 weight gear oil? Like it makes a difference.
Going to xerox some paperwork and fedex it to the supplier.
Funny how some additive/base oil suppliers we used call the gear oil GL "SERVICE DESIGNATIONS" a grade. So, in certain circles, its a service designations "GRADE" and along with the viscosity GRADE. And, slang term weight seems to be used by consumers. Doesn't make it wrong or right and again, who cares what you call it. The edjewcashun and Engrish doctorates can come along and argue here if they want.
So, who here walks into the auto part store asking where the service designation GL5 is located?
BTW, it annoys me when the word "anti-foam" or "antifoamers" are used to explain Si levels in motor oil, atf, gear oil..... in the UOA or VOA sections. Hate it. The refineries and blending plants I worked in called that part of your additive package a defoamer and another used inhibitor.. Maybe its just location dependent.
Gotta run. Going to pick up some GL5 grade gear oil for my car and some thick weight oil, both hopefully with enough antifoam, for my engine and gearbox
Or, maybe I should ask for GL5 level and 80w90 weight gear oil? Like it makes a difference. Going to xerox some paperwork and fedex it to the supplier.
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