250 Gripper Diff (Service and Oil?)

I'm not really sure on on the gripper diff specifically but I've just done a gearbox oil change on my 265 with factory lsd. Opie oils recommended fuchs titan suntofluid as probably the best oil out there. To change it was easy. Take off tray from under the car, undo sump plug to release old fluid. Once drained replace with plug and new washer. Then the fill back I pulled back the passenger front wheel liner and then the white bung just unscrews by hand. I used a piece of garden hose to feed up to the engine bay and just filled up. Takes about 2.4l

 

I'm sure they do recommend that product, for a very good reason too.

Best oil out there? On what grounds?

 

I wouldn't have a clue however I've bought oil off them for years and happy to take the advice.

 

Ok. I wondered where that had come from, but was a personal accolade rather than Opie.

 

I was always told to run the oil that keeps the syncros happy. I run stock oil on my ndo with gripper diff.

Id use elf nfp if its a 250 pk gearbox as they are fussy and the wrong oil gives a poor shift. I tried the fuchs in our old 250 and shift was poor, did not rate it. Went back to oem elf nfp and was fine.

 

I could be talking bollocks, but as far as i know the Renault gearboxes have bronze synchros. Because of this, they should really only be run with GL-4 spec oil as GL-5 spec contains additional additives (typically sulphur) which react with bronze synchros and can damage them. This could be why you and others have reported their gearbox weren't happy with Fuchs (or other oils) as that's a GL-5 oil.

 

I emailed Millers today with the direct question of a Megane 2 NDO box with plated Gripper LSD

The box we have has Millers CRX LS 75/90 NT+ in it, I asked if the oil was suitable and provided the required protection of the yellow metal parts, this was their response -

“Yes it will protect yellow metal components in the gearbox – sounds like the right product for the job”

Thoughts ?

For info - We previously used the Fuchs GL5 oil in a Clio200 box and not long after the oil change the box had to come out due to synchro issues ! We didn’t use it again in the rebuilt box.

 

I work in the industry and I wouldn't be asking Millers anything. But each to their own I guess.

Manufacturer approved every time. Unless you're buying a Total, Shell, Castrol, Mobil product I'd steer clear. (Other similar majors)

Anyone can buy a base oil and an additive package.

Not anyone can spend the amounts on R&D these manufacturers do.

 

You've basically confirmed my long-term suspicion that Millers and their miracle nanodrive oils are just marketing bull!

Is there truth in what I said above, regarding GL-4 vs GL-5 gearbox oils and bronze synchros? Always good to have someone in industry on here to pick their brains!

 

It's something i will need to lookup, I've not known of specific issues regarding gearbox components having adverse reaction to extreme pressure additives, they exist in both specs.
gl4 and gl5 are just API specs. The numbers do not correlate to one being"better" than the other.

If you want my advice, stick with the major brands with the correct approval.

I now work for a distributor of Total lubricants. My previous employer is Total.

 

This gearbox component issue doesn't seem to lead anywhere. None of the majors that I can find list anything that would react with a common metal.

 

Did some more research on this and managed to find a few things, thought this was good to share as the ideal gearbox oil for these cars has been debated for a long time.

https://www.rymax-lubricants.com/updates/the-differences-between-gl-4-and-gl-5/
https://www.penriteoil.com.au/knowl...-between-api-gl-4-and-api-gl-5-gear-oils/1036
https://www.widman.biz/uploads/Transaxle_oil.pdf

All of these sources confirm that GL-5 has approximately double the "extreme pressure additives" as GL-4, which consists of Sulphur or Phosphorus. They also confirm that these additional additives accelerate yellow metal (copper alloy) synchro wear, with Pentrite stating that when a GL-5 oil is used in a gearbox with synchros, it can create up to 4 times the amount of copper in used oil analysis as that of a GL-4 product.

The original Elf oil is GL-4 and after reading these sources, I would definitely stick with a GL-4 oil.

 

So after much discussion with gripper and Opie Oils we’ve decided to try Fuchs Syncro GL4 oil with the addition (if required) of Redline friction modifier. I must say the LS oil we are using from Millers seems fine with no nasty selection issues but it is a GL5 oil so may not be the best for the yellow components. I’ll keep you updated.

 

GL-4 = Hypoid offset of the crown wheel and pinion. GL-5 = Same as GL-4 but with addition of shock loads. These API classes does not say anything about synchro compatibility. The almost double additive in the GL-5 is buffered nowadays (like it has been the last 15-20 years), so they won't eat brazz/bronze synchros. Genuine oil from the big distributors will not have unbuffered agents, like fake oils might have. Additional (old) MIL classes do have a copper corrosion test included for safety. Most tranaxles does use GL-4, as they have the add pack to suit synchonized manual gearboxes. Most GL-5 oils have add pack to suit plain differentials. When choosing oil for a tranaxle, the syncros must be benefited, likely with a GL-4 oil. Some (rare) manufacturers of cars specs GL-5, but then they are designed to use that in the first place. Additionally synchro modulation is made by a certain amount of slip and drag in the synchros. Additives play a big role in that (do not add MoS2 to gearboxes), and also the kinematic viscosity at 100 C plays a role. GL-5 in the same marked viscosity (like 75W-90) often have higher KV than a GL-4 oil of the same marked viscosity. NFP is on the thin side for cars on track, but excellent in road cars. No idea to invent the wheel again, use certified and trusted oils.

 

Here's me just banging some cheap s*it it from CES

No wonder I have a box issue!

 

Well the Fuchs Synchro is in with no friction modifier, first impression after a couple of miles is the gear change down the box is not as slick as with the Millers !! I guess we’ll find out when next on track. If there’s an issue during the first track session then I’ll put Millers back in until we decide what to try next.

Note - the drained Millers definitely had a ‘yellow metal’ haze to it

 

Fuel consumption might be worse off if it's creating more friction