What Transmission Fluid Do I Need?

[BradleyW]

Hello,
I plan to change the transmission oil.
I was under the impression that I need 75W80 GL-5.
However, my PDF service manual suggests I use 75W80 GL-4.
See attachment, thank you.

MEGANE III 1.6 Petrol 2009 - BZ0H - K4M 848 - 5 Door Hatch.

[GiveMeABreak]

Stick to what the manufacturer recommends:- GL5 has nearly twice as many EP additives as GL4. The EP (Extreme Pressure) additives serve to prevent micro welds on the gear flanges that can reach temps up to 800° C. The problem is that these additives do not react well to yellow metals like copper and bronze - i.e. the synchromesh rings in a gearbox - so you really want to stick with GL4 unless Renault specifically allow GL5 for your specific vehicle.

[BradleyW]

Thank you.

I'm confused which is the correct oil. ELF have 2 types of 75W80 GL4.
One called NFJ and the other is NFP.
They both state compatibility with the J and TL4 gearboxes.

However, the data sheet I attached suggests J and TL4 gearboxes require TRJ/NFJ oil. Not NFP!

NFJ:
https://catalog.elf.com/en/products/nq7 ... NFJ-75W-80

NFP:
https://catalog.elf.com/en/products/nq8 ... NFP-75W-80

NFJ appears to be semi-synth.
NFP seems to be for extreme usage and fuel eco friendly. Doesn't say if it is semi or fully synth.

[GiveMeABreak]

I think you'll find the NFP is fully synthetic as it omits 'semi-synthetic' which contains minerals.

I would again stick to NFJ as this is what the technical sheet you have states. The NFP one does seem geared towards the 'highly stressed' use and is probably not needed unless you are racing your car all the time.

[BradleyW]

Thank you for your reply.

I plan to do a gearbox change, not a flush, so whatever oil I put in, it'll mix with oil that still remains in the system. This makes me worried because I don't know what oil is in my gearbox. It could be fully synthetic or semi synthetic.

If I use the semi synth NFJ, and it mixes with fully synth, what may happen?

[GiveMeABreak]

I shouldn't worry too much about that - but surely the gearbox replacement would have the correct oil in already? Whatever you do, don't go flushing or water / steam cleaning the insides of the gearbox (as some do) as that is the sure way to send it to the graveyard. Also be careful about dislodging metal deposits from the replacement box. Although the drain plug should have a magnet to keep these particles grounded you don't want to upset it too much. I would just top up with the correct fresh new oil and you should be fine.

[white exec]

Total-Elf lists manual transmission oil NFJ 75W-80 for your K4M. Tech spec for this is GL4, so where this is specified, avoid using anything which is GL5 or GL4/5.

In PSA boxes, GL5 can compromise the action of the synchromesh, as well as the risk of issues with soft metals that Marc has mentioned.

[BradleyW]

I'm so terribly sorry, I've written it wrong. I didn't mean to say gearbox change. I was meant to say "gearbox oil change", hence why I asked if it's ok for synth and semi synth to mix, just in case my gearbox uses full synth.

Thank you guys.

[GiveMeABreak]

No worries, but regardless, just stick to the recommended GL4 - the TRANSELF NFJ 75W-80 meets the international GL4 specification so is correct for your box. It's not so much the Semi or Fully Synthetic element you should be so concerned about, but the correct specification. GL4 would of been used at factory, so just replace with the same.

[BradleyW]

Super helpful guys, thank you. I'll be tackling the gearbox oil change next week. I'll post some pictures along with my results.

Now I just need to find a new washer that fits. Not sure if it should be a copper crush washer or not. The manual for the car doesn't specify. It just simply says to replace with a new washer.

[Hell Razor5543]

It does need to be the right washer. Give it a few moments and somebody will be along with the right part number.

[BradleyW]

Hopefully so, thank you.

Edit: I suppose any right size washer would work, as long as it is the correct type (example: copper crush washer).

[GiveMeABreak]

I can't help you with Renault parts Bradley - but the dealer should be able to help you and I doubt that it will cost the family jewels.

[BradleyW]

Thank you. I think the part number is 77 03 062 062. I'll call the nearest dealer and see if they have the right washer.

[GiveMeABreak]

No worries - I'm sure you'll have it sorted in no time.