# API GL-5 Manual Transmission Fluid



## racingnismo (May 4, 2003)

Hey B12'ers, it has been a very long time since I have posted here... maybe about 2-3 years? Anyways, my CV's were all ready to go for about 2 years until I finally decided to replace them by changing the entire drive axles.... 

I successfully changed the axles out, but do have a question:

The owner's manual calls for API GL-4 manual transmission fluid, however, I put in API GL-5 manual transmission fluid instead. Does this seem okay or totally wrong to you guys?


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## modenaf1 (Nov 12, 2005)

racingnismo said:


> Hey B12'ers, it has been a very long time since I have posted here... maybe about 2-3 years? Anyways, my CV's were all ready to go for about 2 years until I finally decided to replace them by changing the entire drive axles....
> 
> I successfully changed the axles out, but do have a question:
> 
> The owner's manual calls for API GL-4 manual transmission fluid, however, I put in API GL-5 manual transmission fluid instead. Does this seem okay or totally wrong to you guys?


Ooops :-/ I just threw in 90 weight oil in mine. Was I supposed to use special fluid? I have an 89 with the GA16i and 5sp manual.


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## Popkorn (Nov 16, 2003)

racingnismo said:


> Hey B12'ers, it has been a very long time since I have posted here... maybe about 2-3 years? Anyways, my CV's were all ready to go for about 2 years until I finally decided to replace them by changing the entire drive axles....
> 
> I successfully changed the axles out, but do have a question:
> 
> The owner's manual calls for API GL-4 manual transmission fluid, however, I put in API GL-5 manual transmission fluid instead. Does this seem okay or totally wrong to you guys?


Hey Brah, long time since I seen you around. Your Sentra still holding the road like a champ?
API (American Petrolium Institute) GL ratings are like any other dino lube. They keep refining it and making it suposedly better. So each year or whenever they come up with a better batch they raise the GL rating. Guess it's up to GL 5 now? Is GL4 still available? In the late 80's there was no such thing as GL5. All GL ratings are reverse compatible. Alls you really need to worry about is the viscosity. 90wt is fine. I used a multi viscosity cuz our temps range from 30ish in the winter to 95F or so in the summer. 
Ever see the GL ratings on a can of motor oil? Must be 20 or more acronyms on the better blends.


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## Bror Jace (Apr 26, 2003)

_"API (American Petrolium Institute) GL ratings are like any other dino lube. They keep refining it and making it suposedly better. So each year or whenever they come up with a better batch they raise the GL rating. Guess it's up to GL 5 now? Is GL4 still available? In the late 80's there was no such thing as GL5. All GL ratings are reverse compatible."_

No they are not. Modern GL-5s are not as troublesome as they once were, but the extreme pressure additives used to be corrosive to synchronizers in modern syncromesh trannies. Initially GL-4 used less EP additives and was less aggressive (corrosive) to soft/yellow metals. Currently, they substitue newer, boron-based EP agents for sulphur, phosphorous, etc ...

Take a wiff of a typical gear oil. Smell the sulfur? This chemistry can be corrosive to synchro rings.

Like I said, it's not the serious problem it once was. Some of them are dual-rated ... but I wouldn't use one that isn't. Plenty of dual-rated 75W-90 oils out there.

My #1 pick would be:

http://www.specialtyformulations.com/MTL-R.htm


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## Johnny-wonk (Jan 28, 2003)

A few SE-R guys made the mistake of using somthing other then the recomended GL4 and there gears got stripped.

Go get some Royal Puprle Max Gear, Redline, or even Lucas has a GL4 rating for some of there thicker stuff.

If GL5 was just a better version of GL4 and GL4 a better Version of GL3 and so on dont you think they would just sell ONLY GL5? :waving:


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## Slacky (May 31, 2004)

my 89 sentra was getting a little touchy with 5th, i changed my axels and put gl5 in and within hmmm a week of going to work and back my fifth gear syncro was GONE, so id say that gl5 is still a little corrosive. i cant remember which brand i bought at the time for it but it was the wrong choice thats for sure. I put penzoil gl5 80w 90 in my se-r trans, havent had a problem yet (9 months)


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## SuperSentra4203 (Dec 17, 2002)

It is proven that heavy weight oil (any rating) in stock manual transmissions isn't good. That's why in the early 80's Borg-Warner transmissions (Now known as Tremec) used ATF. Gear lubricant causes too much pressure with the gears and such. Pressure equals heat, and you know the rest. As far as the SE=R guys, they are well aware their notoriously weak stock transmission sucks. GL rating had nothing to do with the transmissions failing.


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## Bror Jace (Apr 26, 2003)

*SuperSentra4203*, you got the basics right, but your reasoning needs a bit of polish:

Heavier oils in any kind of unit cause resistance to flow and excessive fluid friction ... which generates excessive load on the motor and heat. Using a straight 50 weight (or even a 20W-50) in an air-cooled engine might do this (depending on the application).

2) Correct, the GL rating won't cause catastrophic failure of a transmission ... but could accelerate synchro wear ... and it's my contention that these are usually the first things to go in most modern syncromesh transmissions.

I'm no Royal Purple fan, but some have used their 75W-90 with success. Just be sure you get their gear oil and _not_ their lightweight syncromesh fluid which is designed for use in trannies calling for ATF. 

Red Line and Amsoil offer 100% synthetic GL-4 gear oils. Both are good choices.

My favorite is still the Specialty Formulations gear oils. :thumbup: New, 100% synthetic (rea PAO & Ester formula) and friction modified _specifically_ for syncromesh transmissions ... as opposed to other gear oils which are designed primarily for differentials. 

Last I knew, the owner of the company drove a Nissan pick-up and did quite a lot of experimenting using his own vehicles to fine tune syncro engagement.


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## Johnny-wonk (Jan 28, 2003)

SuperSentra4203 said:


> As far as the SE=R guys, they are well aware their notoriously weak stock transmission sucks. GL rating had nothing to do with the transmissions failing.


I drive a B13 NX2000. Yes I am well aware that our trannys are kind of weak. BUt what does that have to do with someone putting the wrong tranny fluid in their cars and then the gear*s* stripping?

Im not talking 5th gear pop out or 3rd shearing under boost. Im talking about regular driving and after a week or two the gears were stripped. Its happend to pretty much every SE-R guy who put the wrong tranny fluid is his tranny...and NOT because of anything else.

the GL rating does matter. Listen to the guys telling you it doesnt and I bet they wont be offering to buy you another tranny or rebuild your gears when you find out it does...


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## SuperSentra4203 (Dec 17, 2002)

Actually, this info comes from my traning by both Valvoline and Exxon-Mobil. I took training courses for my last job. If your car called for a certain rating of fluid from the factory many years ago, you can run any from that time period to present, and It will not void the factory warrenty if applicable. All a rating states is that it meets or exceeds mandated specifications and qualities. Also, manufactures of transmission for factory vehicles often change material and/or quility of syncros often, thats the nature of mass production. Only certain companies stick to a certain material specifacations and dont change, i.e. Borg-Warner/Tremec, Getrag, Hewland.


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## Bror Jace (Apr 26, 2003)

*SuperSentra4203*, I wonder if their recommendation comes from the fact that highly corrosive GL-5 additive packages are getting harder and harder to find?

Maybe, but with all the great GL-4 and dual GL-4/GL-5 approved oils currently on the market, why take a chance to merely save yourself $5-10 on something that only needs replacement every few years.

And just to clarify for some reading this, The "GL" rating applies to the additive package in the oil (metallics, etc ...). The weight/thickness is the number system: 75W-85, 80W-90, 75W-140, etc ... The two are not necessarily related.

Generally, it's the weight that protects the input shaft and other load-bearing parts of the tranny with the proper thickness of hydrodynamic film of oil (based on design, machined tolerances, etc ...). The barrier additives such as sulfur, ZDDP, moly, boron and calcium protect against any metal-to-metal contact that can occur under high-load conditions. 

Of course, too-heavy a weight of oil can lead to missed (or incomplete) shifts as it is slow to be squeezed out between the gears, synchros, etc ... Missed shifts can lead to catastrophic gear stripping. I bet that's what happened to some of the folks the *wonskter* mentioned above.


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## NissanNiNjA (Dec 21, 2004)

Listen to the guys that are telling you about using the wrong kind of stuff.

I was dumb and didnt even think about it when replacing my trans about 2 weeks ago. 2nd drive the car went on was about 200miles.... I lost 2nd and 4th and 5th has been getting angry for the last 2-3 days....

I will be replacing the entire trans soon, and I WILL be putting royal purple max gear back into it.


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## ahardb0dy (Nov 9, 2003)

Is synthetic gear oil compatible with the B-12 tranny? I stopped at a mobil station one day that does oil changes and stuff and the guy said he didn't think synthetic was compatible with the seals????


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## SuperSentra4203 (Dec 17, 2002)

It's compatible for any trans. Synthetic is just a higher quality man made lubricant. There is no reason it would not be compatible.


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## Bror Jace (Apr 26, 2003)

_"[Synthetic's] compatible for any trans. Synthetic is just a higher quality man made lubricant. There is no reason it would not be compatible."_

Modern synthetic lubricants have been formulated to be seal friendly ... and the seals are much better nowadays.

It's been this way for about 2 decades.


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## ahardb0dy (Nov 9, 2003)

I thought it would be ok I just wanted to check


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## racingnismo (May 4, 2003)

I think this pertains to the synthetic compatibility. So, in the past, this is what I have heard:

"Don't change to synthetic engine oil, if you are not going to stick with it. The synthetic oil will cause the gaskets in the unit (in this case the engine) to swell. If you switch back to the normal non-synthetic oil, the swollen gaskets will actually shrink and cause the seals to be broken allowing for all types of leakage and havoc..."

I know this is about engine oil and you may have already known that... but I don't even know if it is true to today's oil's, or can be used as a rule of thumb for tranny oil...


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## SuperSentra4203 (Dec 17, 2002)

racingnismo said:


> I think this pertains to the synthetic compatibility. So, in the past, this is what I have heard:
> 
> "Don't change to synthetic engine oil, if you are not going to stick with it. The synthetic oil will cause the gaskets in the unit (in this case the engine) to swell. If you switch back to the normal non-synthetic oil, the swollen gaskets will actually shrink and cause the seals to be broken allowing for all types of leakage and havoc..."
> 
> I know this is about engine oil and you may have already known that... but I don't even know if it is true to today's oil's, or can be used as a rule of thumb for tranny oil...



That may have applied when synthetics first came out, but it's completely untrue now.


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## gordonb1 (Nov 7, 2005)

Some time ago, the local mechanic put 10W30 engine oil in my B12 5-speed tranny when I expected him to use a heavier weight gear oil such as 75W90. Will this cause damage? Its cool here in the winter - about zero F here right now, but hot - up to 90s in the summer. Is 10W30 safe?

Thanks, Gordon


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## dreamteam (Jul 29, 2005)

gordonb1 said:


> Some time ago, the local mechanic put 10W30 engine oil in my B12 5-speed tranny when I expected him to use a heavier weight gear oil such as 75W90. Will this cause damage? Its cool here in the winter - about zero F here right now, but hot - up to 90s in the summer. Is 10W30 safe?
> 
> Thanks, Gordon


Ha ha, I was wondering when someone was going to mention this!

Gears are gears.
What they need is lubrication.
AND they are not too picky about it either.

After running my 4 speed tranny around for almost a year with next to nothing for lube,(NOT intentional) there was no noticable wear.

Threw some straight 30 non-detergent in it and never looked back.


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## Bror Jace (Apr 26, 2003)

*dreamteam*, you might have gotten away using any old oil in your tranny, but most synchronized trannies are best served by using the proper luve ... and it is not 10W-30 ... especially the newer formulas with fewer metallic additives.

*gordonb1*, I'd sniff ariound and get some proper oil before spring rolls around. Your tranny calls for 75W-90? Being as far north as you are, you'd probably get away with a slightly thinner 75W-85 as well.

Definitely go with a good synthetic as you have cold starts half your year.


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## Slacky (May 31, 2004)

i just picked up some lucas 80w-90 see how that works, i will let u guys know if this link is every brought up again, i usually use penzoil which hasnt failled me yet but they didnt have any today and im not super picky as long as its not synthetic or synthetic blend


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## Bror Jace (Apr 26, 2003)

I'm not sure about the Lucas gear oils. In general, I avoid their stuff. Their products are usually competent ... but nothing special. They have a name because they sponsor CORR and other motorsports series ... not because their formuals are better than any other out there.

I especially avoid their HD Stabilizer goo. 

The fact that the gear oil is 80W-90 and not 75W-90 suggests to me that it is purely mineral-based and not synthetic ... not even hydrocracked mineral oil. You live in Conn so you'll have to judge if it's OK for winter use. If it's less than great, you can leave it in until next November-December and switch to something else.

Pennzoil Marine 75W-90 is good stuff. The back of some bottles even say "Real PAO & ester formula." That's what you want in a synthetic gear oil. Once you know it's 'real' synthetic, then the additive package comes into play. I prefer the non-corrosive boron and moly additives over the sulphur, zinc and phosphorus formulas. Chevron makes a few (their Delo line) ... but I can't get it around here.


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## Slacky (May 31, 2004)

ic... iw ill have to look for that next time i go to change fluids weather it just be regular maintenence or a unavoidable job due to another blown clutch orrr a shot tranny. So far in my driving today for the first time in a week the lucas seems to have more cusion, shifting gears is noticably smoother


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