gearbox and differential oil change

[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/top ... &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.