Hey guys, it happens not all the time but quiet often, I have an SRE shifter installed and synthetic oil in the tranny a couple thousands ago. And Sometimes I have a hard time to take it out of the reverse and getting it into 5th, beleive hard time getting it into 3rd is a common for SRE. Sometimes when getting it into 2nd ther is a noise like the clutch wasn't pressed. Is my tranny going???? And my clutch is almost gone, just have no time to put in 5th gen setup) Besides that I have the rattling noise, but it started after I put the catback on, not shure but it might be related to the tranny.... Thank you!!Any input is appreceated!

 

Will putting the stock shifter back help anything?(of course it would have to be cut )

 

Specifically what fluid is in your transmission. Short shifters in my experience make shifting a little more difficult. Improper clutch adjustment can cause a world of problems getting into gear depending on how badly the clutch is adjusted.

 

Shame on me but I don't know what kind of fluid, since it has been done at a local Mobil station, just asked them synthetic. And this problems have started lately, it was perfectly fine before... One more question, if I put the stock shifter back in and cut will it benefit in shortning the throw a little?

 

I've driven a stock but cut down shifter and I liked it better than the STS' I've driven. You need to find out what fluid it is. It's possible the retards there put an incompatible fluid in your trans, causing your synchros to not work as they should.

 

The right one is GL-4? And if they did put the wrong fluid will changing it to the right one help anything or the rebuild would still have to be done? Thanks a lot for the help!

 

Lets imagine its the wrong fluid could it cause the rattling also?

 

Is the rattling consistent or just sometimes. Mine does this in the morning when the engine is warming up. The cat heatshield somehow rubs slightly against the shifter rod when I shift but once the engine is all warmed up, it disappears, probably because the heatshield is nice and hot and had expanded. I just added some locktite onto the shifter linkage bold last weekend for peace of mind and I decided to bend some parts of the headshield more to keep the rattling noise from happening. It's gone now.

As for getting your shifter out of gears, it could be because your clutch is just worn down too much, the engagement point is out of wack. That's just my opinion but I might be wrong. Also I had some hydraulic leak back then and it was making it hard for me to get in and out of gears. I replaced the master and slave after that and all is fine.

Somehow, the SRE does seem difficult to shift into 3rd at times. I would usually let go of the shifter and grasp it again and just smoothly push towards 3rd, then it goes in! It's a quirk but I won't complain much from a $20 STS.

 

I've got an idea, sometimes the simplest things are the ones we overlook. Get under the car and see if all the bolts on the shift linkage and shifter support rod are tight. That might explain the rattling, the funky shifting, etc.

 

Ok, thank you very much, will do so and get back here later.

DR-Max: Nevermind about the question in the other thread

 

Anyone interested in the fact that Mobil does not make a GL-4 synthetic gear oil? When I inquired about gear oils on their tech line, I was told that they do not make anything that is compatible with GL-4 applications....... I don't know what they put in your trans, but I would get it out and look at Redline, Pennzoil or Specialty Products; all of whom make full synthetic GL-4 rate gear oils..............

 

My SRE is hard to get out of reverse also. I wouldnt worry about that.

 

Thanks we will see. Thanks God I have warranty

 

One more thing: when my car is cold I can shify perfectly, but after a while when it warms up all those problems start like difficulty shifting...Do you know what could it be related to? Thanks

 

Have the fluid flushed out and filled with the proper stuff.

 

I have checked the receipt today and it says that they put 80W90 fluid in it.... What kind of fluid is that? Is it correct one? Thanks.

 

It should also state the gear oil type "GL-4, GL-5". If they used a non GL-4 oil,or a combination GL-4/GL-5 type, it is wrong. And as I stated earlier, Mobil does not make a GL-4 synthetic gear oil........................

 

Weight (80w-90) is one piece of info about the oil - it describes how thick it is. This tells you what temperature range it's designed for.

The GL-4 (or GL-5) spec is a different piece of info that says something about the chemistry of the oil and how slippery it behaves. Manual transmissions don't work well with the slipperiest oils money can buy; in fact GL-4 is the proper spec for a Maxima, and GL-5 is supposedly too slippery for proper function. But it's not far off (I'm using a GL-5 without problem).

You can call the shop and ask them for *specific* information about what gear oil was used. If they don't say about it being GL-whatever, at least get the precise name so you can google it. If they can't give you a specific name, it's an OSHA safety violation. So don't accept "I dunno".

Dave

 

Jeez......like we don't have enough bad information already........GL specs refer to the API requirements for metals compatiblity, and have NOTHING to due with "slipperiest" (whatever that is) propeties in oils. GL-4 API spec gear oils are compatible with the alloy syncro rings in these transmissions. Any lube that is GL-5 rated (alone or as a "combo" spec) lube contain an additive that, by the definition of GL-5, is CORROSIVE to these syncro rings. So if your concerned about "slipperiest", use what ever you want (in fact, **** in your transmissions); but if you want your gearbox to live, learn what in the Hell GL specs are all about.............My God; the stupitidity...........

 

Thanks, I will call them to find out.And thank you JFP in PA for the god info

 

I said the API spec "says something about the chemistry of the oil and how slippery it behaves". To be more technical and specific: EP (Extreme Pressure additives) are approx doubled in a GL-5. The reason is to protect gears that are loaded with heavy shock, so that the high pressure on the gear faces does not cause metal-to-metal bonding that leads to wear.

There are two practical differences between GL-4 and GL-5 because of this change.

1) Active EP additives (sulfur, phosphorus) are a portion of the EPs present in BOTH oils, and it's the active EP additives attack the synchros. GL-4 attacks synchros too, only less aggressively because it has less active EP additives. How aggressive depends on how much copper is present in the synchros.

2) The other EP additives (nonreactive solids, such as moly, graphite, borate, Teflon) reduce friction. They also "tend to make the oil too slick, so the blocking rings have trouble gripping the gear cones to slow the gears". Hence my use of the word "slippery".

The above comes from Robert Bowen's How to Rebuild and Modify your Manual Transmission.

The increase in the use of double- and triple- cone composite-face synchros coincides with the new recommendations of GL-5 in the transaxles. Both the multi-cone and composite-face innovations exist to increase the friction of the synchro on the gear cone, so it suggests adaptations for the lower friction environment of a GL-5-lubricated box.

See above. GL-4s are only LESS aggressive.

As do the GL-4s. See above.

Hmm, your reading comprehension may have caused a disjoint here - I said that manual gearboxes do NOT benefit from extra slippery (high additive) oils.

Yet in your curt, angry lashings, you provided no content or evidence to support your position. You mention that we should all go 'learn' directly from the API specs, which are not publically available - in fact they are only available for purchase. So how do you know the contents of these? If you can provide the API spec texts, that would be helpful.

The only documentation that I know of on this subject is Nissan TSB number NTB94-100, which states that GL-5 or GL-4 are recommended for all Nissan FWD cars.

As my company used to design gearboxes, I will look into obtaining these at work and report what I find.

Dave

 

Check under the car to see if there is anything rubbing, such as the heat sheild.

 

I have the Courtesy STS and it's always been a little notchy but then again, our synchros suck.

 

I said the API spec "says something about the chemistry of the oil and how slippery it behaves". To be more technical and specific: EP (Extreme Pressure additives) are approx doubled in a GL-5. The reason is to protect gears that are loaded with heavy shock, so that the high pressure on the gear faces does not cause metal-to-metal bonding that leads to wear.

There are two practical differences between GL-4 and GL-5 because of this change.

1) Active EP additives (sulfur, phosphorus) are a portion of the EPs present in BOTH oils, and it's the active EP additives attack the synchros. GL-4 attacks synchros too, only less aggressively because it has less active EP additives. How aggressive depends on how much copper is present in the synchros.

I agree that the GL-4 has some level of the same components (primarily there for the benefit of limited slip differentials); however, the very low level of sulfur or phosphorus containing compounds (as well as others) are there to a large degree as artifacts of manufacturing technologies (e.g.: at near trace levels due to the use of common blending/manufacturing equipment) rather than as specific ingredients of the formulation. In the GL-4 formulations, they are below specific levels in order to meet the API specs.
2) The other EP additives (nonreactive solids, such as moly, graphite, borate, Teflon) reduce friction. They also "tend to make the oil too slick, so the blocking rings have trouble gripping the gear cones to slow the gears". Hence my use of the word "slippery".

While I’m sure Mr. Bowen has a basis for his comments, without additional data to support his conjecture, I cannot concur with this statement.

The above comes from Robert Bowen's How to Rebuild and Modify your Manual Transmission.

The increase in the use of double- and triple- cone composite-face synchros coincides with the new recommendations of GL-5 in the transaxles. Both the multi-cone and composite-face innovations exist to increase the friction of the synchro on the gear cone, so it suggests adaptations for the lower friction environment of a GL-5-lubricated box.

Actually, multiple cone and composite faced syncro assemblies have been in use for many years in some makes (European and Asian as well as US), and were developed to address the need for better shifting characteristics in a wide variety of gear box applications, including medium and heavy duty trucks, where they are better at reducing the rotational speeds of higher mass gears during the synchronization process. As many of these applications do not spec GL-5 gear oils, and in some cases do not require the use of any GL rating, I again cannot concur with the above statement(s).

Quote:
GL-4 API spec gear oils are compatible with the alloy syncro rings in these transmissions.


See above. GL-4s are only LESS aggressive. Correct, but more of a semantic point than a technical explanation, much akin to saying that water is less aggressive to a metal than acid.

Quote:

Any lube that is GL-5 rated (alone or as a "combo" spec) lube contain an additive that, by the definition of GL-5, is CORROSIVE to these syncro rings.

As do the GL-4s. See above. Yes, at near trace levels, to meet the API specs………..

Quote:

So if your concerned about "slipperiest", use what ever you want (in fact, **** in your transmissions);

Hmm, your reading comprehension may have caused a disjoint here - I said that manual gearboxes do NOT benefit from extra slippery (high additive) oils.

As for the "harshness" of my response, as a life-long member of both the SAE and the API, I’ve gotten increasing tired and disrespectful towards anecdotal comments on websites that the uninitiated attempt to pass off as facts. On some B15 (Sentra, SER, SER Spec V) websites, a quick search produces a wealth of examples of people claiming that switching from GL-4 rated lubes in their 6 speeds (same gear box in the current Maxima) to GL-5, or even non GL rated lubes significantly improves the shifting, particularly in the cold. Some have even espoused the use of GM rated motor oils used in gearbox applications. While moving to a lower vis or higher lubricity fluid does produce lower effort shifts; their long term usage has also resulted in a significant number of gearbox failures related to the synchronizer alloy rings (as well as bearing surface failures, most likely as the result of the high metallic sludge levels from the ring failures).

Interestingly, in conversations with gear oil formulators, including Mobil, Pennzoil and Royal Purple (to name a few); everyone has uniformly recommended against using non GL-4 lubes. Mobil went as far as to say that they “Have no compatible gear oils for Nissan’s with GL-4 spec gear box applications,” and that the use of their products “Could result in premature synchronizer failures.” As I was inquiring about their Mobil 1 synthetic gear oils, which are all GL-5 rated, their statements are very telling. I have had similar synro failure comments from Pennzoil, but in their case, they had synthetic GL-4 rated products to offer as an alternative.

Quote:
but if you want your gearbox to live, learn what in the Hell GL specs are all about.............My God; the stupidity...........

Yet in your curt, angry lashings, you provided no content or evidence to support your position. You mention that we should all go 'learn' directly from the API specs, which are not publically available - in fact they are only available for purchase. So how do you know the contents of these? If you can provide the API spec texts, that would be helpful.

The API specs are available, for a nominal fee (a membership fee); and are the intellectual property of the API. As part of becoming a member, you agree to “not publish or replicate in any form, electronic or otherwise, without their specific written permission,” materials they identify as their intellectual properties. As someone who also owns “intellectual property,” I fully understand and comply with their request, as I would expect the same in return. However, this fact does result in a perfect scenario: Do not take what I have to say at face value, got to the source (in this case, the API), read, and learn the facts for yourself. As I mentioned previously, the web is rife with anecdotal comments and opinions that get passed off as facts. Paying a membership fee to gain access to a database is really no different that paying tuition to attend a college or tech school, you are getting access to intellectual properties (knowledge) that took a lot of time and expense to assemble. This is one of the reasons that such fees are usually tax deductible as well……….

The only documentation that I know of on this subject is Nissan TSB number NTB94-100, which states that GL-5 or GL-4 are recommended for all Nissan FWD cars.

I have read this TSB, and discussed it with two Nissan zone reps as it is contrary to the data published in their factory service manuals (FSM’s going back more than a decade, and up through 2006 models list only GL-4 rated gear oils for Maximas). One informed me that I was “better off following the FSM”; while the other told me that the inclusion of GL-5 ratings in the TSB was an accommodation to “vociferous dealers that constantly complain that aftermarket GL-4 rated gear oils are harder to find and more expensive than the more common GL-5 oils”. As these comments represent direct conversations, and are therefore difficult to confirm; I would suggest you look at the API ratings of Nissan branded gear oils sold by dealers: They are GL-4 rated. I wonder why that is..............

As my company used to design gearboxes, I will look into obtaining these at work and report what I find.

Dave

 

Thanks for taking the time to offer more information. I too have struggled with the condensed 'recommendations' on the web for a long time, and lacking data it's nearly impossible to make an informed decision.

1) Active EP additives (sulfur, phosphorus) are a portion of the EPs present in BOTH oils, and it's the active EP additives attack the synchros. GL-4 attacks synchros too, only less aggressively because it has less active EP additives. How aggressive depends on how much copper is present in the synchros.

JFP: I agree that the GL-4 has some level of the same components (primarily there for the benefit of limited slip differentials); however, the very low level of sulfur or phosphorus containing compounds (as well as others) are there to a large degree as artifacts of manufacturing technologies (e.g.: at near trace levels due to the use of common blending/manufacturing equipment) rather than as specific ingredients of the formulation. In the GL-4 formulations, they are below specific levels in order to meet the API specs.

That is the one piece of information which I can't find available - the quantity/concentration of active (aggressive) EPs vs nonreactive EPs. It would seem an oil rated for "GL-5" only could have a different formula than one rated for GL-4 and GL-5 by varying this proportion. So I guess the question I have boils down to: are some GL-4/5 rated oils more friendly to a GL-4 designed gearbox? Is there any difference between the typical GL-5 and GL-4/5, or are some oil manufacturers simply misleading the consumer in saying their GL-5 also meets GL-4? Are the GL-4 and GL-5 specs open enough to truly permit a cross-listing, and if so, do all such cross-listed oils present the corrosion problem?

2) The other EP additives (nonreactive solids, such as moly, graphite, borate, Teflon) reduce friction. They also "tend to make the oil too slick, so the blocking rings have trouble gripping the gear cones to slow the gears". Hence my use of the word "slippery".

JFP: While I’m sure Mr. Bowen has a basis for his comments, without additional data to support his conjecture, I cannot concur with this statement.

His comment makes sense and aligns with common experience - GL-5s tend too lead to crunching due to insufficient synchro clutching, and the accelerated wear would round the edges of the synchro friction surface, which would exacerbate the problem. Do you not agree?

The above comes from Robert Bowen's How to Rebuild and Modify your Manual Transmission.

The increase in the use of double- and triple- cone composite-face synchros coincides with the new recommendations of GL-5 in the transaxles. Both the multi-cone and composite-face innovations exist to increase the friction of the synchro on the gear cone, so it suggests adaptations for the lower friction environment of a GL-5-lubricated box.

JFP: Actually, multiple cone and composite faced syncro assemblies have been in use for many years in some makes (European and Asian as well as US), and were developed to address the need for better shifting characteristics in a wide variety of gear box applications, including medium and heavy duty trucks, where they are better at reducing the rotational speeds of higher mass gears during the synchronization process. As many of these applications do not spec GL-5 gear oils, and in some cases do not require the use of any GL rating, I again cannot concur with the above statement(s).

Perhaps I need to clarify. Double cones, triple cones, and composite faced synchros offer one thing: more friction for clutching. Hence the application to bigger gearboxes. Since the clutching job they are asked to perform hasn't changed significantly (same gears, same RPMs, same geometry, etc), then why the extra friction? I'm suggesting that it *might* be to offset the extra lubricity of a GL-5 oil.

Quote:
JFP: Any lube that is GL-5 rated (alone or as a "combo" spec) lube contain an additive that, by the definition of GL-5, is CORROSIVE to these syncro rings.

As do the GL-4s. See above.

JFP: Yes, at near trace levels, to meet the API specs………..

Quote:
JFP: So if your concerned about "slipperiest", use what ever you want (in fact, **** in your transmissions);

Hmm, your reading comprehension may have caused a disjoint here - I said that manual gearboxes do NOT benefit from extra slippery (high additive) oils.

JFP: As for the "harshness" of my response, as a life-long member of both the SAE and the API, I’ve gotten increasing tired and disrespectful towards anecdotal comments on websites that the uninitiated attempt to pass off as facts.

I had been wondering why you lashed at my post, but looking back perhaps you thought I had written it in response to you. I wrote that first post for the OP, who I felt might not have been clear on the meaning of 80w-90 vs. GL-4. I anticipated that the OP might have been brushed off with some nonsense when he talked to the service shop, and that a little background was in order. Hence the anecdotal format.



JFP: Interestingly, in conversations with gear oil formulators, including Mobil, Pennzoil and Royal Purple (to name a few); everyone has uniformly recommended against using non GL-4 lubes. Mobil went as far as to say that they “Have no compatible gear oils for Nissan’s with GL-4 spec gear box applications,” and that the use of their products “Could result in premature synchronizer failures.” As I was inquiring about their Mobil 1 synthetic gear oils, which are all GL-5 rated, their statements are very telling. I have had similar synro failure comments from Pennzoil, but in their case, they had synthetic GL-4 rated products to offer as an alternative.

I read similar info on Mobil's website, where they claim their GL-5s could only be used in GL-4 spec'd rear end boxes, which obviously means they feel it should not be used around synchros.

Do you know anything about Neo gear oils? I have had their 75w-90HD GL-5 in my RX-7, and just recently filled my Maxima tranny with it. I will consider draining (and saving) the Neo from the Maxima if it indeed is an aggressive GL-5.

JFP: The API specs are available, for a nominal fee (a membership fee); and are the intellectual property of the API. As part of becoming a member, you agree to “not publish or replicate in any form, electronic or otherwise, without their specific written permission,” materials they identify as their intellectual properties. As someone who also owns “intellectual property,” I fully understand and comply with their request, as I would expect the same in return. However, this fact does result in a perfect scenario: Do not take what I have to say at face value, got to the source (in this case, the API), read, and learn the facts for yourself. As I mentioned previously, the web is rife with anecdotal comments and opinions that get passed off as facts. Paying a membership fee to gain access to a database is really no different that paying tuition to attend a college or tech school, you are getting access to intellectual properties (knowledge) that took a lot of time and expense to assemble. This is one of the reasons that such fees are usually tax deductible as well……….

From the outside, that's hard to know. You're the first person I've had this kind of discussion with who apparently has opened and read these documents. Unfortunately my experience with such things is that they tend to cost $100+ for a small document or membership that may or may not answer my question. Really, I am not interested in breaking intellectual property laws, but a couple of excerpts or a few numbers would be sufficient. The point is that if I paid for every ASTM, API, etc standard that I'm slightly curious about, I'd have a pile of paper and no money for servicing my car, and only *some* of my questions would be answered.

I checked around work; we do not have any information about API specs since we deal with industrial gear drives.

The only documentation that I know of on this subject is Nissan TSB number NTB94-100, which states that GL-5 or GL-4 are recommended for all Nissan FWD cars.

JFP: I have read this TSB, and discussed it with two Nissan zone reps as it is contrary to the data published in their factory service manuals (FSM’s going back more than a decade, and up through 2006 models list only GL-4 rated gear oils for Maximas). One informed me that I was “better off following the FSM”; while the other told me that the inclusion of GL-5 ratings in the TSB was an accommodation to “vociferous dealers that constantly complain that aftermarket GL-4 rated gear oils are harder to find and more expensive than the more common GL-5 oils”. As these comments represent direct conversations, and are therefore difficult to confirm; I would suggest you look at the API ratings of Nissan branded gear oils sold by dealers: They are GL-4 rated. I wonder why that is..............

That's great information, but also unfortunate and very telling of Nissan. But without that information, it suggests (strongly) to an outsider that the difference between choosing a GL-5 and a GL-4 is semantic, which apparently it is not. There are plenty of other examples where the dealer says to do one thing, but a *much* cheaper alternative is available off the shelf.

Dave

 

Thanks for taking the time to offer more information. I too have struggled with the condensed 'recommendations' on the web for a long time, and lacking data it's nearly impossible to make an informed decision.

1) Active EP additives (sulfur, phosphorus) are a portion of the EPs present in BOTH oils, and it's the active EP additives attack the synchros. GL-4 attacks synchros too, only less aggressively because it has less active EP additives. How aggressive depends on how much copper is present in the synchros.

JFP: I agree that the GL-4 has some level of the same components (primarily there for the benefit of limited slip differentials); however, the very low level of sulfur or phosphorus containing compounds (as well as others) are there to a large degree as artifacts of manufacturing technologies (e.g.: at near trace levels due to the use of common blending/manufacturing equipment) rather than as specific ingredients of the formulation. In the GL-4 formulations, they are below specific levels in order to meet the API specs.

That is the one piece of information which I can't find available - the quantity/concentration of active (aggressive) EPs vs nonreactive EPs. It would seem an oil rated for "GL-5" only could have a different formula than one rated for GL-4 and GL-5 by varying this proportion. So I guess the question I have boils down to: are some GL-4/5 rated oils more friendly to a GL-4 designed gearbox? Is there any difference between the typical GL-5 and GL-4/5, or are some oil manufacturers simply misleading the consumer in saying their GL-5 also meets GL-4? Are the GL-4 and GL-5 specs open enough to truly permit a cross-listing, and if so, do all such cross-listed oils present the corrosion problem?

2) The other EP additives (nonreactive solids, such as moly, graphite, borate, Teflon) reduce friction. They also "tend to make the oil too slick, so the blocking rings have trouble gripping the gear cones to slow the gears". Hence my use of the word "slippery".

JFP: While I’m sure Mr. Bowen has a basis for his comments, without additional data to support his conjecture, I cannot concur with this statement.

His comment makes sense and aligns with common experience - GL-5s tend too lead to crunching due to insufficient synchro clutching, and the accelerated wear would round the edges of the synchro friction surface, which would exacerbate the problem. Do you not agree?

It would be a “stretch”. The lubricity differences between GL-4 and 5 oils are real and measurable, but I have seen many applications of low vis, high lubricity lubes that did not lead to problems with syncro assemblies. GM uses some pretty slick motor oils in their Corvette gearboxes (as do other OEM’s) without difficulties, so I cannot credit all of the syncro issues to the frictional properties of the lube……………..

The above comes from Robert Bowen's How to Rebuild and Modify your Manual Transmission.

The increase in the use of double- and triple- cone composite-face synchros coincides with the new recommendations of GL-5 in the transaxles. Both the multi-cone and composite-face innovations exist to increase the friction of the synchro on the gear cone, so it suggests adaptations for the lower friction environment of a GL-5-lubricated box.

JFP: Actually, multiple cone and composite faced syncro assemblies have been in use for many years in some makes (European and Asian as well as US), and were developed to address the need for better shifting characteristics in a wide variety of gear box applications, including medium and heavy duty trucks, where they are better at reducing the rotational speeds of higher mass gears during the synchronization process. As many of these applications do not spec GL-5 gear oils, and in some cases do not require the use of any GL rating, I again cannot concur with the above statement(s).

Perhaps I need to clarify. Double cones, triple cones, and composite faced synchros offer one thing: more friction for clutching. Hence the application to bigger gearboxes. Since the clutching job they are asked to perform hasn't changed significantly (same gears, same RPMs, same geometry, etc), then why the extra friction? I'm suggesting that it *might* be to offset the extra lubricity of a GL-5 oil.

I would have to say “possibly” to your conjecture. While the size and layout of many gearboxes remain similar, the lubricity differences between GL-4 and 5 oils may not be the only reason to go to multiple cone or friction facings, particularly as transmissions that spec other types of oils that are lower in lubricity, also use multiple cone layouts. One major change in gearbox design has to do with front drive layouts and cable shifters. If you think about how a syncro works when you shift, it is basically “slamming on the brakes” to slow down the gear to gain synchronization. In the “old days,” you had direct mechanical linkage systems that provided true mechanical leverage advantages to help the transmission during this process. With cable shifters, there is significant “give” in the cables (the current SER Spec V’s use the current Maxima gearbox, and are cable operated, and well known to be balky shifters in the stock configuration. Add a short shifter, and it really gets ugly). So, if you cannot use positive leverage to enhance the braking effect of the syncro, why not increase the frictional surface area with multiple cones or differing surfaces to enhance the effect……….

Quote:
JFP: Any lube that is GL-5 rated (alone or as a "combo" spec) lube contain an additive that, by the definition of GL-5, is CORROSIVE to these syncro rings.

As do the GL-4s. See above.

JFP: Yes, at near trace levels, to meet the API specs………..

Quote:
JFP: So if your concerned about "slipperiest", use what ever you want (in fact, **** in your transmissions);

Hmm, your reading comprehension may have caused a disjoint here - I said that manual gearboxes do NOT benefit from extra slippery (high additive) oils.

JFP: As for the "harshness" of my response, as a life-long member of both the SAE and the API, I’ve gotten increasing tired and disrespectful towards anecdotal comments on websites that the uninitiated attempt to pass off as facts.

I had been wondering why you lashed at my post, but looking back perhaps you thought I had written it in response to you. I wrote that first post for the OP, who I felt might not have been clear on the meaning of 80w-90 vs. GL-4. I anticipated that the OP might have been brushed off with some nonsense when he talked to the service shop, and that a little background was in order. Hence the anecdotal format.



JFP: Interestingly, in conversations with gear oil formulators, including Mobil, Pennzoil and Royal Purple (to name a few); everyone has uniformly recommended against using non GL-4 lubes. Mobil went as far as to say that they “Have no compatible gear oils for Nissan’s with GL-4 spec gear box applications,” and that the use of their products “Could result in premature synchronizer failures.” As I was inquiring about their Mobil 1 synthetic gear oils, which are all GL-5 rated, their statements are very telling. I have had similar synro failure comments from Pennzoil, but in their case, they had synthetic GL-4 rated products to offer as an alternative.

I read similar info on Mobil's website, where they claim their GL-5s could only be used in GL-4 spec'd rear end boxes, which obviously means they feel it should not be used around synchros.

Exactly my point, they told me that their products are not compatible with the alloys used in our syncro assemblies, and could cause problems. At least they are upfront about it…………………..not all lube purveyors are.

Do you know anything about Neo gear oils? I have had their 75w-90HD GL-5 in my RX-7, and just recently filled my Maxima tranny with it. I will consider draining (and saving) the Neo from the Maxima if it indeed is an aggressive GL-5.

I know they exist, but remain circumspect about their products as they do not offer technical data on their oils, and have not been particularly forth coming when inquiries are made to obtain data. I find it troubling that they do not list any API data on their website………….



JFP: The API specs are available, for a nominal fee (a membership fee); and are the intellectual property of the API. As part of becoming a member, you agree to “not publish or replicate in any form, electronic or otherwise, without their specific written permission,” materials they identify as their intellectual properties. As someone who also owns “intellectual property,” I fully understand and comply with their request, as I would expect the same in return. However, this fact does result in a perfect scenario: Do not take what I have to say at face value, got to the source (in this case, the API), read, and learn the facts for yourself. As I mentioned previously, the web is rife with anecdotal comments and opinions that get passed off as facts. Paying a membership fee to gain access to a database is really no different that paying tuition to attend a college or tech school, you are getting access to intellectual properties (knowledge) that took a lot of time and expense to assemble. This is one of the reasons that such fees are usually tax deductible as well……….

From the outside, that's hard to know. You're the first person I've had this kind of discussion with who apparently has opened and read these documents. Unfortunately my experience with such things is that they tend to cost $100+ for a small document or membership that may or may not answer my question. Really, I am not interested in breaking intellectual property laws, but a couple of excerpts or a few numbers would be sufficient. The point is that if I paid for every ASTM, API, etc standard that I'm slightly curious about, I'd have a pile of paper and no money for servicing my car, and only *some* of my questions would be answered.

I checked around work; we do not have any information about API specs since we deal with industrial gear drives.

Just remember that API specs are not formulation parameters, but rather a series of tests to find out how any given formula should be classified. Most of the specifics are ASTM and/or SAE tests for physical parameters such as flow, load carrying, shear properties, etc. Several of the tests evaluate the corrosion properties of the hot oil over time on standard pieces of metal known as test coupons. You measure the weight loss, deformation and delaminating of the coupons before and after exposure. This is one critical area for GL classifications.

Interestingly, in the past, there has not been a huge amount of attention paid to the heat transfer properties of gear oils, even though any good oil chemist will tell you that heat transfer properties are the number one function of oil, followed by lubrication. In addition, one of the largest advantages that synthetics have over “dino” oils is a higher heat transfer capability. Mobil 1 engine oils are typically around 20% better than their comparable non-synthetic products, but this is not something you often find discussed………..

I know that becoming a member of the API is not in the cards for everyone, unless they can justify it for business reasons. And, quite plainly, a lot of the spec data is ponderous to leaf thru.

The only documentation that I know of on this subject is Nissan TSB number NTB94-100, which states that GL-5 or GL-4 are recommended for all Nissan FWD cars.

JFP: I have read this TSB, and discussed it with two Nissan zone reps as it is contrary to the data published in their factory service manuals (FSM’s going back more than a decade, and up through 2006 models list only GL-4 rated gear oils for Maximas). One informed me that I was “better off following the FSM”; while the other told me that the inclusion of GL-5 ratings in the TSB was an accommodation to “vociferous dealers that constantly complain that aftermarket GL-4 rated gear oils are harder to find and more expensive than the more common GL-5 oils”. As these comments represent direct conversations, and are therefore difficult to confirm; I would suggest you look at the API ratings of Nissan branded gear oils sold by dealers: They are GL-4 rated. I wonder why that is..............

That's great information, but also unfortunate and very telling of Nissan. But without that information, it suggests (strongly) to an outsider that the difference between choosing a GL-5 and a GL-4 is semantic, which apparently it is not. There are plenty of other examples where the dealer says to do one thing, but a *much* cheaper alternative is available off the shelf.

True enough, but with far too many cases of problems around when people of used the wrong lubes; and the rather hefty price for a new gearbox (nearly $2K, in a crate), following the designer’s specs seems prudent………
Dave

 

As a follow-up:

I spoke at length today with a lead engineer at Royal Purple, who explained to me that yes, you can indeed have a GL-5 that is also fully qualified as a GL-4. He says he gets this question all too often, and *he* said much of this myth is due to internet car forums. He said that there are many possible ingredients to put into an EP additive package that meet GL-5 specs, and it's no big trick anymore to keep it from attacking yellow metals. It seems that either obsolete or cheap petroleum-based GL-5s are the only fluids that present significant risk of attacking the yellow metals, and anyone here asking about it won't be using this stuff.

He said that RP Gearmax's passed the ASTM D-130 Copper Corrosion test with a 1A rating (the highest possible), and in fact produced 1A-level results at much higher test temperatures and durations.

I also called the folks at Neo, and they assured me it is 100% compatible with GL-4 synchromeshed gearboxes for the same reasons mentioned by the RP rep.

My own research yielded verbage that indicates many GL-4/GL-5 rated synthetics from Neo, Royal Purple, Amsoil, Redline, etc.

Dave

 

Not to "rain on the parade" but it is very interesting that RP (http://www.royalpurple.com/prodsa/mgeara.html), who do not make GL-4 rated gear oils, would say that their GL-4/5 rated products are “OK” for use in Nissan gearboxes. Apparently neither Pennzoil (who make both GL-4 and GL-5 rated lubes), or Mobil (who only make GL-5 rated synthetics) are capable of duplicating Royal Purple’s feat, and therefore recommend either using a GL-4 only rated lube (in the case of Pennzoil), or not using their products entirely (in the case of Mobil 1). Sorry, but I've had problems with various of RP's claims in the past, and still do not completely trust either them or their products....................

Perhaps even more interesting is the primary use for the ASTM test cited: ”automotive gasoline; aviation gasoline; aviation turbine fuel; copper-corrosion; copper strip; corrosiveness to copper; natural gasoline; 77.060 (ASTM ACTIVE STANDARD: D130-04e1 Standard Test Method for Corrosiveness to Copper from Petroleum Products by Copper Strip Test Detection of Copper Corrosion ASTM (D130): Detection of Copper Corrosion from Petroleum Products by the Copper Strip Tarnish Test: Some sulfur compounds that remain in the petroleum product after refining are corrosive to various metals. This method is used to determine the corrosivity of petroleum products (including aviation gasoline, aviation turbine fuel, automotive gasoline, and natural gasoline) to copper.)”. While it could be used to test gear oils, it is primarily a fuels test, and this test, by the by, does not have a “1A” classification listed, it is a rated in “SI” units…………………

As for Neo, as I said earlier, I do not know much about them, but they do not list any API specs on their website and have not responded to my requests for technical data on their products. Perhaps they could send you a tech spec sheet to confirm their statements..........................

 

In that link you provided, it says that it is safe for GL-4, just click the link on the right at "Royal Purple's Advantages".

And I have a .pdf datasheet that he emailed to me that says "Max-GearŽ also is safe for GL-4 applications or bronze synchro gears."

As for your disdain of the marketing claims and inferences out there, ALL the brands do it. Amsoil and Redline are far from being perfect pastors leading the sheep to pure truth.

First, he declined to cite that test due to it's weakness, (it is just a strip of copper bathed in the 121°C oil for 3 hours), but I asked for it since Amsoil cites it. He said (and I think we agree) that the color of tarnish is not the ideal way to evaluate that the chemicals are non-aggressive.

Second, I think you're missing something in the test spec - gear oils are classified in a range of 1A-4(C?), where 1A is the highest. Amsoils were rated 1B. Perhaps there is something for oils listed separately from the fuel.

I made the request and it's supposedly on the way.

My point in all this is not to change your mind - but I want to share in case anyone else is reading that indeed there is significant attention and support that says the major premium synthetic GL4/GL5s are more than safe for use in our transmissions.

Dave

 

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