Help with gearbox oil choice for PK4 Renault gearbox

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I have a Megane RS MK4 2019 plate. The car is running the PK4 manual gearbox thats in the previous RS model (MK3) thats known for issues.

My car has 10k on the clock recently im getting clicking/knocking at <4mph and a droning noise pitched with wheel speed at >35mph. Any gear, neutral, clutch in or out. The car drives perfectly and goes into all gears perfectly. The noise is either the LSD bearings or the output shaft bearing. I wont know for sure till the gearbox specialist gets inside the gearbox and looks.

I want to put the best possible oil in the car when the gearbox is fixed to hopefully stop this happening again. The OEM oil is "Elf Tranself NFX SAE 75W". However this is the newest version of the oil it was formally known as "ELF TRANSELF NFP 75W-80"

Iv been looking online high and low for my options and i came across a guy that tests oils out using a machine and one oil caught my eye "Total Traxium Gear 8 75W80". Im going to link below what im talking about.

Total Traxium Gear 8 75W80 - Test 1
Total Traxium Gear 8 75W80 - Test 2 @100C

Elf Tranself NFJ 75W80 - Test 1
Elf Tranself NFJ 75W80 - Test 2 @100C

Elf Tranself NFJ 75W80 - Results test 1 - 0.47 of wear.
Elf Tranself NFJ 75W80 - Results test 2 @100C - 0.17 of wear

Total Traxium Gear 8 75W80 - Results test 1 - 0.01 of wear.
Total Traxium Gear 8 75W80 - Results test 2 @100C - 0.02 of wear.

The difference of these two oils is clear on these videos. The stuff that's suggested for my gearbox seems to be rubbish.... The specs of both these oils match as far as i can see. However my car has an Torsen LSD and iv been reading about friction modifiers etc. I have no clue if this Gear 8 stuff would be ok to run in my gearbox because of the LSD. Also i have no clue about additives etc... There is also a company called K-Tec who are big in the Renault Sport world and they have suggest Millers 75w-90 to people instead of the OEM stuff thats w75-80. Im lost, i want to prevent myself from having thousands of pounds of bills again. Also the car has brass synchros if that makes a difference to oil options.

Elf Tranself NFJ 75W80 - Data Sheet Here
Total Traxium Gear 8 75W80 - Data Sheet Here

I know there is more to oils than just the tests iv shown in the videos... and im no expert here.... Do i just stick with OEM oil or can i go with something like the Gear 8?? Its weird how its such a common issue on there gearbox's, im hoping i can boost my protection with a better oil choice. Cheers
 
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I don't think the total will help with bearing failure, but what do you have to lose? Undortunately, we don't know from those tests if the friction is lower, there's no indication of power consumed. Torsen style differentials do require some friction between the gears and housing to work.
 
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Helical gear diffs make their own noises and tend to have a clunky/clicky lash. None of the GL-4 fluids have an LS additives to worry about.

Did the youtube 1-arm bandit tester test some Elf Tranself NFX SAE 75W?

I would change the gear oil now and send it out for analysis, prior to visiting the 'gearbox specialist'.

Is there a drain plug magnetic? If not, add one to monitor wear during normal service intervals.

And, there is no such thing as best possible gear oil. Its a balance of cold weather shift quality, hot gearbox **** quality, and wear prevention. If the engine is modified for more power, then the gearbox fluid could run hotter on average. If so, OE grade recommendations are meaningless.

Wonder if they went thinner to cater to 'shift' complainers, to improve fuel economy, or to free up some power.

So, I'd vote for the Traxium Gear 8. Another option is the Total Traxium Gear 6 or Ravenol MTF-1 75w85 since jumping to the Millers 75w90 might be a bit excessive concerning the ability to shift when cold. Most don't have patience to nurse a manual transmission until fluid comes up to temp. Millers also has a CRX 75w80 NT+ which matches the OE grade recommendation.
 

Siye_MeganeRS

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Helical gear diffs make their own noises and tend to have a clunky/clicky lash. None of the GL-4 fluids have an LS additives to worry about.

Did the youtube 1-arm bandit tester test some Elf Tranself NFX SAE 75W?

I would change the gear oil now and send it out for analysis, prior to visiting the 'gearbox specialist'.

Is there a drain plug magnetic? If not, add one to monitor wear during normal service intervals.

And, there is no such thing as best possible gear oil. Its a balance of cold weather shift quality, hot gearbox **** quality, and wear prevention. If the engine is modified for more power, then the gearbox fluid could run hotter on average. If so, OE grade recommendations are meaningless.

Wonder if they went thinner to cater to 'shift' complainers, to improve fuel economy, or to free up some power.

So, I'd vote for the Traxium Gear 8. Another option is the Total Traxium Gear 6 or Ravenol MTF-1 75w85 since jumping to the Millers 75w90 might be a bit excessive concerning the ability to shift when cold. Most don't have patience to nurse a manual transmission until fluid comes up to temp. Millers also has a CRX 75w80 NT+ which matches the OE grade recommendation.
He only did a test on the NFJ which has been the OEM spec oil for my gearbox for years (this is the oil that the bearing would have failed on) however only recently they changed/rebranded it to NFX. The video doesnt give me confidence in the oil i can say that much.

I cant test the oil. The cars going to the garage today to get the box removed and send over to the specialist. My hope now is i can prevent/minimise this from happening again. Iv seen many people with the PK4 gearbox on the previous gen megane ask about changing oil and no one has an answer. I imagine because they dont anything about oil's in the detail some people do on here. They just think OEM is always better because its suggested by Renault. I dont believe its the best for the gearbox looking at that test. That stuff is what was in my gearbox box from factory. Iv looked through that fella's video on other gearbox oils. The NFJ gets terrible score compared to others just in general.

I will say this, the car drives fine and selects gears fine. This is a bearing issue... So i have to keep that in mind when selecting an oil... Would viscosity help with bearing wear prevention?? Would a thinner oil help out bearings more? I know the video shows extremely less wear for the Gear 8... but in my case will that also translate to less wear on my bearings... As again thats the aim here. Gears seem to be fine. Its also not uncommon for bearings to go in the PK4 box. So prevention and good maintenance is key. I need to select and oil and change it at a good interval.

Not sure at this point if there is a magnet on the drain plug, i think there might be one built into the bottom of the gearbox though as iv seen one split open on a youtube video and there was a big magnet in the sump of the gearbox.

Im sold on the Traxium Gear 8... im just worried it wont be good enough because my car has an LSD as iv read LSD cars need special oil. I dont have any experience in oils or whats needed in an oil for an LSD. Iv seen people mention about the brass synchros, so some oils must react with the brass. Again i dont know what elements in the oil can do this... I dont have a spec sheet for something like that and i dont know how to find it. I dont want to put any oil in and ruin something in my box not long after fitting.

The car is running 330bhp with 500NM of torque. It needs some good protection and maybe more than your everyday average car. The oil test shows the wear @0.02 @100c temps on the Gear 8 and 0.17 on the NFJ. Im not sure how these tests translate to the real world actually in the gearbox.... But i can certainly see the Gear 8 offers better protection on the video at heat as it only jumped 0.01 from its standard test temp.

Im stuck in what to do. The video has sold me on the Gear 8 oil but im kinda looking for a second opinion that its not going to mess anything up.... or not be good enough for LSD or something of that nature. Its not a cheap part to replace and the LSD's arnt cheap. Dont want to make a mistake that could cost me thousands.

In regards to Millers CRX 75w80 NT+ this is also an option as i know KTEC uses millers oils too. So they must be ok... I do want the best protection while not completely ruining my shift feel i guess. I do warm my engine oil upto temp religiously. I allow it to get to 90c before i get my foot down.

EDIT: There is a wear test for Millers Oils CRX 75W90 NT:-

Millers Oils CRX 75W90 NT - Test 1
Millers Oils CRX 75W90 NT - Test 2- 100C

Millers Oils CRX 75W90 NT - Results test 1 - 0.23
Millers Oils CRX 75W90 NT - Rest test 2 @100c - 0.05

It seems Millers outperforms The ELF. However this is weight "w75-90" Millers that KTEC suggests people. OEM weight is 75w80..... But it neither come to close to the Gear 8. As they where 0.01 and 0.02 on wear.

If the Gear 8 stuff is compatible in every regard ill probably go for that... If someone can confirm its ok for brass synchros and a Torsen Limited Slip Diff and doesnt have anything nasty in it or lack there off??? Im not sure on the chemical/mineral/additive side of things or however you would say it in regards to the contents in the oil.

Anymore help much much appreciated!!! Thanks.
 
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Siye_MeganeRS

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Millers also has a CRX 75w80 NT+ which matches the OE grade recommendation.

Millers Data Sheet Here

Seems on the Millers CRX 75w80 NT+ it says its for gearbox's "without" limited slip that require API GL4. So its no good.

The Gear 8 stuff doesnt mention if its for an LSD or not...

Not sure where to go from here as nothing is clear on any of the datasheets iv seen and if there is no mention of additives for the diff... then im assuming its a no go.

Cheers
 
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Siye_MeganeRS

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Your helical gear is not a traditional limited slip and will typical have NOTHING to do with LS additives needed for cone/clutch type differentials.
Not sure what you mean mate. Its got a proper Torsen Limited Slip Differential... I know it acts differently to other diff's in terms of how it works but its still an LSD. Its the "exact same" shape and size as say a Gripper LSD... Both the diff bearings that press on either side of the Torsen diff are the same. Im not an expert so you'll have to put it in more layman's terms. The oil you suggested says it not for use with a limited slip. So iv got a LSD but its not really an LSD? Confused.

At this point if better info cant be provided ill just have to go with OEM stuff and hope for the best. Was hoping some oil wizard could point me in the right direction with information to back up the claims. Im not the type to just follow advice blindly. Its the internet afterall.
 
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Learn what a traditional LS is compared to a torsen. The term "proper" doesn't mean a thing. And no, it is not a traditional LSD and has no concern when regarding LS additives used on clutched LSD to eliminate chatter.

 

Siye_MeganeRS

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What EXACTLY does the owner's manual say?
It says refer to maintenance service handbook. Something they never gave me when i bought the car. Strange. Some what iv read on the PK4 box no one really goes outside the OEM elf oil. Except K-TEC who are Renault Sport Specialists. People dont seem to tinker that much with gearbox oils.
 
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It says refer to maintenance service handbook. Something they never gave me when i bought the car. Strange. Some what iv read on the PK4 box no one really goes outside the OEM elf oil. Except K-TEC who are Renault Sport Specialists. People dont seem to tinker that much with gearbox oils.
Do the research and find out what OEM actually recommends. IN WRITING.
 

Siye_MeganeRS

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Do the research and find out what OEM actually recommends. IN WRITING.
I wrote this at the start in my opening post... Its in the video i sent too.... Its the Elf stuff thats now called "ELF NFX 75w". This is the stuff the bearing failed on... Car has 12k on clock.

The PK4 gearbox has been around for like 10 years. Its always the same stuff. Elf NPJ or NFK.... Both have been discontinued and superseded by ELF NFX. You can see from the video's i sent how good the oil is on that test. Not very. Hence my post on a search for something better. Looks like im just going to have to stick to the OEM stuff. Doesn't fill me with confidence but hey! better than nothing. TBH i though on a forum like this someone would have been like BOOM this is better because of this, this and this.
 
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I wrote this at the start in my opening post... Its in the video i sent too.... Its the Elf stuff thats now called "ELF NFX 75w". This is the stuff the bearing failed on... Car has 12k on clock.

The PK4 gearbox has been around for like 10 years. Its always the same stuff. Elf NPJ or NFK.... Both have been discontinued and superseded by ELF NFX. You can see from the video's i sent how good the oil is on that test. Not very. Hence my post on a search for something better. Looks like im just going to have to stick to the OEM stuff. Doesn't fill me with confidence but hey! better than nothing. TBH i though on a forum like this someone would have been like BOOM this is better because of this, this and this.
They don't sell Renault in the USA so your last sentence makes little sense.

You wrote "The OEM oil is "Elf Tranself NFX SAE 75W".". That does NOT address what I am asking.

Contact Renault and ask them. Not what brand. But exactly what oil type and specifications.
 

Siye_MeganeRS

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They don't sell Renault in the USA so your last sentence makes little sense.

You wrote "The OEM oil is "Elf Tranself NFX SAE 75W".". That does NOT address what I am asking.

Contact Renault and ask them. Not what brand. But exactly what oil type and specifications.
To be clear Renault suggest NOTHING but "Elf Tranself NFX SAE 75W". There is no suggestions beyond that. There is no viscosity suggestions or guidelines. Its use "Elf Tranself NFX SAE 75W" or nothing. The French do things weird.
 

Siye_MeganeRS

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Sounds like a bad wheel bearing to me.
Its not a wheel bearing mate. Iv jacked up the car, spun the wheel. You can here the grinding noise from inside the gearbox. Also its now in the garage. Iv had 3 extremely experienced mancanics look at it. They all said diff bearings.
 
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I wrote this at the start in my opening post... It’s in the video i sent too.... It’s the Elf stuff thats now called "ELF NFX 75w". This is the stuff the bearing failed on... Car has 12k on clock.
But as is nearly always the case there’s no indication the failure was due to the oil.
 

Siye_MeganeRS

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But as is nearly always the case there’s no indication the failure was due to the oil.
This is true but i was hoping to find something that would offer some better protection on the bearings. Extending there lifespan, obviously not oils are equal... I want the best of the best for my application. I dont want to have to deal with the time/money involved having to get the gearbox opened up again and fixed again.
 
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I have never seen a design or materials defect cured or even significantly mitigated by lubricant choice. The grade and license here is adequate for that gearbox and there are no magic fluids that can fix a bad bearing.
 

Siye_MeganeRS

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I have never seen a design or materials defect cured or even significantly mitigated by lubricant choice. The grade and license here is adequate for that gearbox and there are no magic fluids that can fix a bad bearing.
I appreciate what your saying, however the video's iv sent say otherwise. The Gear 8 oil vs the ELF oil shows that oil is a huge factor when it comes to wear moving metal components. Some oils offer better protection over others.

Im not asking oil to fix a bad bearing. The bearing is getting replaced. The cars currently in the garage for that very reason. What i want to do is give my new refurbished gearbox the best oil to "PREVENT" this happening again... or least extend bearing life. This is the very reason we use certain oils over others right???
 
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