gearbox and differential oil change

[Allan280]

Hi
Having recently purchased Z4M Roadster I was looking at having all the fluids changed I have got the Castrol 10 -60 engine oil was enquiring what spec and manufacturer is best for the gearbox and differential .

Any additives required to go in the diff oil as I had a previous car with LSD and it needed an additive to go in the oil. Any parts required ie new seals for the sump plugs.

 

[PDJ]

There is a label on the side of the gearbox for the spec of the oil

Yes there a friction modifier required for the diff oil.

I think I have posted the specs after I changed mine this would have been around May/June time

 

[AndyBeech]

Gearbox I'm going for a combo of Red Line MTL + D4 ATF. A mix of the two gets pretty good reviews. 2 litres in total.

Diff I'm trying out Millers CRX Fully Synthetic Nanodrive NT + Plus Gearbox Oil GL4 GL5 MT-1 75w 140. Not for any particular reason but just felt like something else this time! 2 Litres again.

Can't buy new seals for the plugs, either a new plug or re-use. Supposed to replace I believe but sure using the same one again is fine.

 

[Allan280]

Hi
Thank you both for that information what ratios do you mix the two suggested products at before putting in the car.

 

[RedUn]

I use oem bmw fluids, never had an issue, not sure why you would mess around trying others but thats just me, simple :lol:

 

[AndyBeech]

I use oem bmw fluids, never had an issue, not sure why you would mess around trying others but thats just me, simple :lol:

To be fair BMW stuff is only rebranded Castrol I believe so nothing ‘special’ as such. OEM stuff (especially fluids) I find to be ridiculously priced for what it is, but then can say that about most parts for this car! :lol:

OP, the diff oil is premixed so just add until full.
Gearbox I believe put all the MTL one in then fill up with the D4 until it’s full, probably have around half a litre left.

 

[RedUn]

I use oem bmw fluids, never had an issue, not sure why you would mess around trying others but thats just me, simple :lol:

To be fair BMW stuff is only rebranded Castrol I believe so nothing ‘special’ as such. OEM stuff (especially fluids) I find to be ridiculously priced for what it is, but then can say that about most parts for this car! :lol:

OP, the diff oil is premixed so just add until full.
Gearbox I believe put all the MTL one in then fill up with the D4 until it’s full, probably have around half a litre left.

Very true, the diff oil was quite specific from memory.

I can't remember how much I paid last time but it wasn't horrific, but maybe I've just got used to ///M tax :headbang:

 

[Monster666]

I found this post when I was looking into changing my Z4MR gearbox oil

https://z4-forum.com/forum/viewtopic.php?f=9&t=99480&p=1455675&hilit=gear+change+bad+gear+change#p1455675

 

[Argenta]

"CDV delete" doesn't matter much on a Z4M (maybe on a Z4?) and I did not feel any improvement in gearchange whatsoever.

However, changing the gearbox oil did. Since the change it's like warm, from cold.

RedLine MTL 70W-80 - gearbox (don't put ATF oils in it - it's a manual for christ sake)
Motul Gear Competition 75W-140 - differential.

 

[AndyBeech]

(don't put ATM oils in it - it's a manual for christ sake)

If you mean ATF as in the D4 a lot of people use it as an additive with good results, use it together with MTL. Opie Oils also recommended it to help smooth the gear changes out.

 

[Argenta]

Hehe sorry, slipped!

I just can't fathom why anyone would want something EVEN slicker than a Z4M gearbox with Redline in it.

 

[RedUn]

(don't put ATM oils in it - it's a manual for christ sake)

If you mean ATF as in the D4 a lot of people use it as an additive with good results, use it together with MTL. Opie Oils also recommended it to help smooth the gear changes out.

Just thinking about this, genuinely no one knows better than bmw, opie or not, I'd never advise anyone to mix oils, especially two different types. It might be alright for a while but who knows what damage it could be doing in time? Especially a gearbox that's engineered for changing at high rpm, you can feel the heat from it through the floor of the car, hence I'm not sure adding thinner oil is such a good idea, it'll feel better on a cold morning no doubt but what about when it's running at high temps under load?

For the cost of replacing a gearbox it's just not worth it.

 

[AndyBeech]

(don't put ATM oils in it - it's a manual for christ sake)

If you mean ATF as in the D4 a lot of people use it as an additive with good results, use it together with MTL. Opie Oils also recommended it to help smooth the gear changes out.

Just thinking about this, genuinely no one knows better than bmw

I don't agree with that statement entirely, I think there's plenty of evidence that BMW don't always know best on everything! At the end of the day it's only opinions though, I've researched a lot over the last 6 months, internet (of course! :lol: ), spoke to a few specialists, other owners etc.

Based on this I've made my personal decisions. All I would say is to anyone else is, do as much research as you can and make your decisions from there. Ton of information out there so use it your advantage, lots of real world experiences with different fluids.
FWIW I'll only be using a small amount of D4 with the MTL fluid. Also depends how much, if any, track work you do. Certainly nothing wrong with staying BMW of course.

I would say if Opie were recommending oils that were making gearbox's or otherwise pop they probably wouldn't have a very good rep! They've been in business a long time so have a lot of information and customer feedback on what works and what doesn't. But as said, research is key!

 

[mr wilks]

If you mean ATF as in the D4 a lot of people use it as an additive with good results, use it together with MTL. Opie Oils also recommended it to help smooth the gear changes out.

Just thinking about this, genuinely no one knows better than bmw

I don't agree with that statement entirely, I think there's plenty of evidence that BMW don't always know best on everything! At the end of the day it's only opinions though, I've researched a lot over the last 6 months, internet (of course! :lol: ), spoke to a few specialists, other owners etc.

Based on this I've made my personal decisions. All I would say is to anyone else is, do as much research as you can and make your decisions from there. Ton of information out there so use it your advantage, lots of real world experiences with different fluids.
FWIW I'll only be using a small amount of D4 with the MTL fluid. Also depends how much, if any, track work you do. Certainly nothing wrong with staying BMW of course.

I would say if Opie were recommending oils that were making gearbox's or otherwise pop they probably wouldn't have a very good rep! They've been in business a long time so have a lot of information and customer feedback on what works and what doesn't. But as said, research is key!

Id have to agree , most manufacturers aim to see their cars problem free through the warranty period , after that do they really care ? clearly not if you go by the service intervals they now deem satisfactory .
Similar story with runflat tyres & in particular the chosen profiles Bmw have gone with for far too long when other manufacturers all run bigger ones on same sized rims & similar performance cars .
I switched previous 3 Z4Ms to Millers fluids for engine, diff & gearbox ( just went with the recommendations on the Millers website ) & i'l be doing the same when the 4th ZM arrives next week , ultimately its personal preference but i wouldn't do it if i didn't think it was a improvement over Bmw recommended ones

 

[RedUn]

I love this forum for the different opinions!

For me, the gear change is fine, no need to change it but I appreciate others want to experiment.

Overall if someone thinks they know better than bmw that's fair enough, you pays your money etc just consider the buying power an oem like bmw has, if they wanted miller's it would be no problem.

One area where I do agree though is tyres they have clearly moved on in 10+ years!

 

[AndyBeech]

I love this forum for the different opinions!

For me, the gear change is fine, no need to change it but I appreciate others want to experiment.

Overall if someone thinks they know better than bmw that's fair enough, you pays your money etc just consider the buying power an oem like bmw has, if they wanted miller's it would be no problem.

One area where I do agree though is tyres they have clearly moved on in 10+ years!

Of course, good to get different opinions, don't think you'll go wrong with anything mentioned above, all tried and tested in various ways!

I don't think it's quite as simple as BMW being able to pick whoever they want to supply fluids however. I imagine it's somewhat more complicated and is partly based on who has a supply contract at the time, value for money, profit margins etc etc. Hence why Shell is now the OEM oil supplier not Castrol, not because they are necessarily better, just they now hold the contract to supply.

 

[mr wilks]

I love this forum for the different opinions!

For me, the gear change is fine, no need to change it but I appreciate others want to experiment.

Overall if someone thinks they know better than bmw that's fair enough, you pays your money etc just consider the buying power an oem like bmw has, if they wanted miller's it would be no problem.

One area where I do agree though is tyres they have clearly moved on in 10+ years!

I didn't switch to Millers aiming for better gearchanges , its a brand ive preferred for over 15 yrs & its based on a little more than just experimenting .
Primarily i choose the brand for its engine oils , their high end ones like CFS are proven to run cooler at max & consider that its heat that generally destroys engines id say that's 1 good reason (+ the cold start performance is also a consideration with the S54 ) http://www.millersoils.co.uk/products/0/142

If you do get chance its worth a internet study on the 911 engine failures of the past 10/15 years its no secret that indy garage Hartech are now considered to be producing their rebuilt & improved engines to a better standard than Porsche itself & they will only warranty these engines if the user continues with Millers used in any further oil changes .
Just one of the countless discussions you can find online https://www.pistonheads.com/gassing/topic.asp?h=0&f=48&t=1276175

 

[Jembo]

Given oil degrades, more so with short periods of use & becomes contaminated by fine particles of metal, do any of the oil suppliers publish any of their own recommended time based replacement matrix - I can’t find anything relevant on google.

 

[PDJ]

Given oil degrades, more so with short periods of use & becomes contaminated by fine particles of metal, do any of the oil suppliers publish any of their own recommended time based replacement matrix - I can’t find anything relevant on google.

Too many variables to be able to predict on time alone.

When I worked at a power station the contracted oil company would do oil samples and then recommend oil changes.

I was sent on an oil training coarse run my Castrol and there is so many variables, to a point we sent a used oil and a new oil sample and the results where interesting to say the least. They found traces of things that they say should not be in there when new.

For an oil sample to be a detailed worthwhile report you need to know what oil and other materials are meant to be in the gearbox so you can work out where the particles from the oil sample are coming from.

But lets say there is a trace of synchro metal in the sample are you going to replace the gearbox or just change the oil and be a bit more careful when changing gear or blame the previous owner for missing a gear change.

My personal recommendation would be to change the gearbox and diff oil every year or two,

The first 2 or 3 years from new the owners had a warrantee to fall back on so no great need to worry it is only now they are older that it may become a worry.