MPS6 rear diff oil suggestions

[andy b]

I am approaching the 90,000km service on my MPS6 and have been thinking about having the rear diff oil changed as per preventative service suggestions (every 45,000km under certain operating conditions).

Should I go with the oil provided by my local Mazda dealer, or an aftermarket GL5 80W-90 like Nulon/Castrol/Penrite, or Penrite Limslip 90 which is an 80W-90 with more EP additives to bring it to GL6 level and designed for LSD applications?

Does the MPS6 have a mechanical or electronic rear LSD? And do you have any experiences or preferences?

[kmh001]

There have been numerous discussions here about lubricants which you might find useful. There are two points which I would make; make sure whatever lubricant you chose matches the book specs; if you replace the diff, transfer case and gearbox oil with good synthetic your car will feel like it's gained a few kw due to the reduced friction.

[andy b]

I couldn't really find much regarding specifics on rear diff oil changes (too many MPS3's...) I know the transfer case and rear diff use the same oil, is it worthwhile doing them both at the same time?

[kmh001]

I couldn't really find much regarding specifics on rear diff oil changes (too many MPS3's...) I know the transfer case and rear diff use the same oil, is it worthwhile doing them both at the same time?

yeah I think it is worth doing them at the same time. I would also recommend changing the gearbox oil at least every 40,000km due to the likelihood of soft metal contamination.

Apart from encouraging you to use fully syntehtic oil, I'd be reluctant to recommend a particular lubricant because there's very little available in terms of engineering evidence on lubricant performance and magazine articles and advertising clap trap are usually complete bulsh1t that don't help anyone make an informed decision. However there was a thread here a while back that had a credible looking analysis of gearbox oils done by Amsoil.

Just make sure what ever oil you chose meets the book specs.