Help with gearbox oil choice for PK4 Renault gearbox

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Yes you want the best like so many others. I got that.

And as far as the videos go, the actual ASTM procedure has a specified type of apparatus that must be used, as well as specific test procedures (with a minimum sample size) and subsequently a proper data analysis that includes error bars with repeatability and reproducibility. Is this test following all of that? If not then the “test” is a load of garbage and you are unable to make decisions from the supplied data. Just because it may be visually stimulating doesn’t make it valid.

You also have to determine if the test is applicable to the concern you have with the bearings. Is it?
 
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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.
What I was thinking. Maybe Renault used inferior bearings in that model gearbox.
 
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What I was thinking. Maybe Renault used inferior bearings in that model gearbox.
Or there was just a failure. My old ECHO had an output bearing start to fail early in its life. I replaced them and it’s seen several hundred thousand miles of service since then with no further issues.
 

Siye_MeganeRS

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Or there was just a failure. My old ECHO had an output bearing start to fail early in its life. I replaced them and it’s seen several hundred thousand miles of service since then with no further issues.
Well hopefully this is the case for me. All i know is i bought this car 3 months ago with 9000 miles on the clock and here i am having to get my gearbox sorted. Did you watch the videos i linked the in OP? Both oils go through the exact same test. One preforms badly. Maybe its just best i stick to the OEM stuff. There doesnt seem to be any clear answer if there is a better oil.

The bearings are kinda a common thing in this gearbox. Maybe ill change my gearbox oil every 10k or something instead of looking for the holy grail of gearbox oils. Too complicated.
 

Siye_MeganeRS

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What I was thinking. Maybe Renault used inferior bearings in that model gearbox.
Both the PK4 and PK6 gearbox's are known for it. Its common and these are Renault Sports best models to date. The car runs 300bhp standard. There highest BHP figures in any model yet (and there last, Renault has went full electric now)
 
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Would Renault not offer a contribution or good will gesture considering its only just out of warranty and only had 10k on the clock? Renault dealers are usually pretty good. Certainly better than the Vauxhall dealers I've had the displeasure of dealing with.

There's a wide array of oils suitable for your gearbox. My Wife's Dacia Logan also specifies the Tranself 75w80 which was replaced by the NFX 75w. When I looked many moons ago I noticed the new product was thinner and therefore decided to avoid it.

I've run Fuchs Sintofluid 75w80 and Millers TRX 75w80 without any issues. I think the Millers changes gear slightly smoother but I only swapped the fluids because I was changing the clutch and there's many other reasons why the change might have been smoother.

Personally, if it was mine I'd probably look at Amsoil Manual Transmission Fluid or a Redline MTF of some description. Have a nose on the Old Hall Performance website.

Just to add, your type of LSD does not need any fancy additives.
 
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Well hopefully this is the case for me. All i know is i bought this car 3 months ago with 9000 miles on the clock and here i am having to get my gearbox sorted. Did you watch the videos i linked the in OP? Both oils go through the exact same test. One preforms badly. Maybe its just best i stick to the OEM stuff. There doesnt seem to be any clear answer if there is a better oil.
They aren’t going through the exact same test. Only a standardized test with standard equipment and a statistically significant number of trials yields repeatable results. That test is a joke just like all the rest on the Internet. Pick any of them.
 

Siye_MeganeRS

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Would Renault not offer a contribution or good will gesture considering its only just out of warranty and only had 10k on the clock? Renault dealers are usually pretty good. Certainly better than the Vauxhall dealers I've had the displeasure of dealing with.

There's a wide array of oils suitable for your gearbox. My Wife's Dacia Logan also specifies the Tranself 75w80 which was replaced by the NFX 75w. When I looked many moons ago I noticed the new product was thinner and therefore decided to avoid it.

I've run Fuchs Sintofluid 75w80 and Millers TRX 75w80 without any issues. I think the Millers changes gear slightly smoother but I only swapped the fluids because I was changing the clutch and there's many other reasons why the change might have been smoother.

Personally, if it was mine I'd probably look at Amsoil Manual Transmission Fluid or a Redline MTF of some description. Have a nose on the Old Hall Performance website.

Just to add, your type of LSD does not need any fancy additives.
Thanks for your comment. Im currently in the process of going through AA warrenty. They will however only replace the bearing thats failed and any other bearings that are subject to pre-mature wear because of the one failed bearing wont get touched unless i pay for them separately. I also have to pay for fluids etc. So im going to be in for a bill regardless. Im thinking about £500... but thats hell of alot better than thousands.

If you consider the car is running 330BHP with 500nm of torque which of them oils would you choose with that power mark in mind. Also thanks for clarifying that about the LSD. I know alot of people just suggest to stick with OEM oil. So you would suggest something else and would these be a clear improvement?

Also why is thinner worse (as you decided to avoid)? WIll the shift quality be worse? Does thinner oil offer any advantages? Just makes me wonder why K-TEC use Millers 75w-90 oils for there gearbox changes.

Im starting to think this whole bearing situation is just Renaults bad design. Not really a indication of bad oil... However if there is something better than OEM thats what ill go for. Thanks

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This is what i found regarding the newer ELF oil (There claim on 22 percent extra protection is interesting):-
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Note: This product replaces Tranself NFP 75W-80 and Tranself NFJ 75W-80 and covers their targeted applications.

Benefits:

Up to 0.25% fuel economy with an increase of 22% wear protection compared to precedent products Tranself NFP & NFJ
Advanced protection for synchro components
Outstanding resistance to mechanical shearing
Extreme-pressure (EP) and anti-wear capabilities enable gears to function under the most severe stresses
Unrivalled thermal performance, guaranteeing a stable product even under heavy loads and at high temperature
Particularly stable coefficient of friction ensures satisfactory synchronisation in all conditions
High viscosity index and low pour point ensures perfect lubrication at all temperatures
Very high antifoaming power
Inert to seals
 
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Oil film thickness protects

Unless the gearbox was designed for the thinner fluid from the beginning, I would take the protection of viscosity.

MPG improves with thin gear oil. Weak wristed drivers complain less since thin fluid is easier to shift. So, you make the environmentalists and pathetic drivers happy at the cost of transmission life.
 
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