Any manual transmission oil recommendations?

[CarlSlk350MT]

Going to have the transmission oil changed for a 2005 slk350 manual as I don't think it has ever been changed from birth, yet there has never been any issues and gear changes have always been very smooth indeed. I've been looking at Red Line MT-LV 70W/75W GL-4 Gear Oil, which the Red Line site recommends for the manual transmission - has anyone used this oil? Any other recommendations?

 

[rayhennig]

Be very careful here. I do not know your car but I am aware that many MB manual boxes use auto box fluid - Dex II or Dex III, I can't recall.

You should check with MB for the specification of your gearbox oil. Do not rely on 3rd party website advice.

Just my 2c worth.

Good hunting.

RayH

 

[matthew k]

What an interesting car, there can't be many of those about, any chance of some pictures?

Agree you should ask the Main Dealer, GL4/5 isn't suitable for some manual gearboxes, putting the wrong stuff in could cause damage/make it balky.

 

[MJJ]

I have been having some challenges after a manual box oil change on my S211 recently, and another forum member kindly pointed me to Mercedes own oil spec document - https://bevo.mercedes-benz.com/bevolisten/231.1_en.html

In my case, an 80W gear oil meeting the required MB235.1 standard was awful when the oil was cold, gear selection was very tough, whereas a swap to 75W (MB235.1 also) oil made a night and day difference.

As said above, take the time to find what Mercedes state is the right spec for your car, and use that.

Martin.

 

[Gazwould]

 

[rifiki]

MB have been using auto transmission oil on manual boxes since the 1950s.
If you use gear oil it will be almost impossible to change oil when cold.

 

[John Laidlaw]

Check with Opie Oils, they are forum sponsors and give good advice

 

[Larkone]

https://www.startekinfo.com/StarTek/outside/9511/?requestedDocId=9511

 

[steveq]

I changed the gearbox fluid in my manual 2011 W204 C220 CDI Blue Efficiency a few years ago.
I used the Fuchs Sintofluid.
Here is a link to what I used:-
https://www.opieoils.co.uk/p-981-fu...w-80-synthetic-manual-transmission-fluid.aspx

I thought that the gearbox felt smoother after the change but that could just have been my imagination.

From memory, the gearbox filler and drainer has two different sizes of Allen key. Remove the filler bolt first so you don't get caught out!!

Also, you don't fill the gearbox until it flows out in the same way as the back axle.
I believe it takes 1.5 litres. I suggest that you measure what comes out to doubly check.

 

[CarlSlk350MT]

Done some further research and learned that the SLK manual is very particular about its oil otherwise there would be awful consequences, etc. So decided it was best to go with the only oil MB approves, which happens to be their very own MB 317 oil from their MB235.10 specification. It's expensive stuff and was hoping to find the same stuff on offer for less from the Mobil website where MB gets the oil from. But alas there wasn't anything on offer that matched the 75W/85 viscosity of the MB manual oil, so presumably MB adds something crucial to whatever they use from Mobil. Yet I managed to haggle with MB from £44.44 for two litres to a more palatable £37, which was a bit of a surprise as they don't have a reputation for budging on prices. Anyhow, eagerly waiting for the garage to fix the transmission leak, replace the subframe [also managed to haggle that from MB from £850 to £698], replace the diferential oil and then pass the MOT.

Thank you to everyone who offered advice and help.

 

[Gazwould]

Another done on genuine oils...

75W85 is too thick and specialist oil companies don't list such an application for a 2005 350 SLK , cold viscosity is crucial and thick cold oil plays a big part in poor gear changes .

That's why the specialists are listing a 75WFE which is actually a 70W75 and the cold viscosity difference is massive .

Specialist oil companies and sellers know WAY more about oil than Mercedes .

I very much doubt Mercedes could tell you what centiStokes that oil is @ 40°C .

 

[CarlSlk350MT]

Another done on genuine oils...

75W85 is too thick and specialist oil companies don't list such an application for a 2005 350 SLK , cold viscosity is crucial and thick cold oil plays a big part in poor gear changes .

That's why the specialists are listing a 75WFE which is actually a 70W75 and the cold viscosity difference is massive .

Specialist oil companies and sellers know WAY more about oil than Mercedes .

I very much doubt Mercedes could tell you what centiStokes that oil is @ 40°C .

Oh dear, have made a bad choice there? Obviously I need to do more homework on this topic and shame this kind of insight wasn't presented earlier. Well it's going to get colder soon, so we'll see. If all does get tricky, I would want to have the oil changed - any particular recommedations for the 75WFE you suggest?

Thinking you are probably generally correct on the idea that Mercedes know less about oils than they should as I'm finding the engine runs the best I've experienced so far on the Amsoil Signature Series 5W-30 oil, which is not on their approved list, than their preferred Mobil 1.

 

[Gazwould]

It's all about money...

Post 5 for my recommendations .

 

[CarlSlk350MT]

It's all about money...

Post 5 for my recommendations .

Yes did see those but couldn't find any other recommendations for them - I just kept seeing the stick to what MB says kind of advice and thought I should play safe snce I don't know a great deal on this. Will defo come back to post 5 if I find the shifts are not as good as they have been. But have to say I've never experienced a bad shift with this gear box whenever it's been cold if it's the original MB oil that's already been in there, so maybe the previous owner had the oil changed to something better.

 

[mioba]

If you ask MB what the oil is, stick with that. MB engineers are not daft and know required oils to meet spec.

 

[Gazwould]

If you ask MB what the oil is, stick with that. MB engineers are not daft and know required oils to meet spec.

Q, should I buy Rip Off Britain genuine ATF fluid for my Merc or the Fuchs equivalent ?

 

[mioba]

would the Fuchs not be sourced in Britain too.

The OP is concerned as to compatabilibity, uncertain.

 

[CarlSlk350MT]

Thought I should update this thread as the hugely recommended MB 317 235.10 oil is not so fantastic after all, especially in cold weather, which I now see was the big glaring warning I should have zoomed in on earlier in this thread.
Before the change to the MB 317 235.10 oil there were no prior gear box issues. Yet the reason for the change was that it seemed a good opportunity to replace both the transmission and rear differential oils while the subframe was being replaced, as I doubted these oils were ever changed since the car was born. Anyhow, all was well and fine just as before, but back then the weather was mild. Then since December onwards when the weather began to go much cooler, going into 1st and 2nd from first start became an ever increasing challenge, yet things would go in smoothly after around ten minutes. Wasn't too bothered at first as wasnt using the car much anyway and thought the gear change resistance should improve when the cold spell lifts.
But things became really bad on the first morning of frost around seven weeks ago when it was a real struggle going into 1st when pulling away, then even more of a battle going into 2nd. Yet 3rd and upwards were fine, although the time for things to settle was increasing too. But the final straw came one frosty morning four weeks when I had no option other than to pull away in 3rd, as it was impossible to go into 1st or 2nd. After around a minute it was time to change down into 2nd, and by now I was thinking the gearbox must have warmed up. But violent crunching was the instant shock result when I tried changing down, and not only that, it was still crunching neutral! So back into 3rd it went along with 4th and 5th being fine after that, then with 1st and 2nd behaving themselves five minutes later.
Right away I thought the MB oil must be replaced asap as I wasn't going to have this everytime it gets cold. So I ordered 2 litres of the Red Line MT-LV 70W/75W GL-4 Gear Oil, which I had asked about at the beginning of this thread, and then had the garage replace the MB oil the other day. Then lo and behold! everything was fine and just as it was before the change to the MB oil when there were no issues whatsover - actually I think the gear shifts are slightly better than ever.
The garage told me they couldn't see anything untoward in the MB oil, but it was 1.65 litres that came out. Ok, a little over the specified 1.5 litres, but that shouldn't have lead to the kind of dramatic issues I was experiencing.

So I'm now thinking that the previous owner must have had the MB oil replaced too. And am surprised there isn't any more in these forums [that I can find] that highlight issues arising from the use of MB 317 oil in cold temperatures for manual gearboxes.

So if anyone is experiencing the same problem in cooler temperatures, then I would strongly urge them to try having the transmission oil replaced with either the Red Line stuff mentioned earlier or with something similar as in post #5. But in anycase get rid of that MB oil if driving in cooler temperatures is unavoidable. Also going to see if I can have my money back from MB.

 

[Gazwould]

Not surprised , the Redine MT-LV centiStoke viscosities are comparable with Millers TRX Synth 75W and Fuchs Titan Sintofluid FE SAE 75W .

All will serve as the above experience .

Genuine gearbox oils are a rip off , not made by the car manufacturer and rarely a data sheet to show the centiStokes .