Hi
I changed oil in diff a week ago. Since that time I think the diff works louder. Is is possible or just my immagination ?
Not a technical answer as I’m no mechanic but just a thought. Could it be that because the new oil is cleaner and thinner it doesn’t have the “sound deadening” properties of the old oil which was no doubt dirty and thicker through use?
Tell me I’m stupid but it seemed feasible to me!
Check you have put the correct grade and type of oil in and that it is at the correct level. If they are both correct stop worrying and enjoy the ride.
Yes. The oil anild its level is fine. I am just maybe i little bit touchy about that. But this is 9 years car with 79k miles on the clock and everything can happen. I also found a short film on YT when somebody lifted the rear and run the car. There was quite loud sound from the diff. I guess my can be similar to that. It is like brake discs rubbing. But the brakes are fine, as well tyres.
I can hear that sound when roof and windows are closed.
Exactly what make grade and spec of oil did you put in.
Mobil SHC Fully Synthetic SAE 75W-90
[quote=Lukas78]
Yes. The oil anild its level is fine. I am just maybe i little bit touchy about that. But this is 9 years car with 79k miles on the clock and everything can happen. I also found a short film on YT when somebody lifted the rear and run the car. There was quite loud sound from the diff. I guess my can be similar to that. It is like brake discs rubbing. But the brakes are fine, as well tyres.
I can hear that sound when roof and windows are closed.
[/quote]
Are you sure it’s diff noise, you say you can hear the noise with the roof up and windows closed. The MK3 is known for road noise coming from behind the seats especially when the roof is up.
Well that is the correct spec oil as you are aware.
I would double check the oil level and if it is correct you just have to live with the noise.
My 55 plate Impreza rear diff got noisy at around 80,000 miles.
I’m getting more inclined to think that the early Mk1 cars 0.65 ltrs, the Mk3 0.7 ltrs and the Mk4 0.6 ltrs have too little oil in their diffs. No actual proof, just a feeling but many of these cars have quiet diffs at over 100,000 miles.
Well I’ve put about 0.85 - 0.9 ltrs.
Everywhere is written that in a factory, Mazda put 0.7 ltrs but when filled more with a new one it won’t affect the diff in a bad way.
I would say that the sound of a diff resonates when the roof is up.
It is not my film, but I found this: https://youtu.be/fzml2xugy2M?t=75
Is it serious if this is it or can I run with that for some time ?
Autolink have a secondhand one in stock.
http://www.autolinkmx5.com/differential-mazda-mx-5-mk3-20-6-speed-371-lsd-used-8928-p.asp
Workshop manual for the diff here
http://www.mellens.net/mazda/Mazda-Miata-2006-2007/differential.pdf
The diff may go on for a good while or it may not. I reckon my Impreza lasted at least 3,000 miles before I got rid of it but it was getting worse noise wise.
Sorry not going to advise how long it will last.
Or maybe this???/
Hmm… so maybe I will wait and see what is going on. It it is louder, harsher etc… I would like to spend money If not sure if this is it.
My car is a nc1 123000 miles, and just had what I thought was a noisy diff fixed… It was a wheel bearing, cheaper than a diff, but still expensive.
With the roof up, so you hear the noise, does it go away if you turn either left or right?
I’ve never heard about something like this one…
No, there is no difference. Anytime when driving, straight, cornering and so on. Still the same sound.
BTW: I don’t have LSD so can I jack one side of the car and run it ? Then only one wheel should be running… am I right ?
I would check then bearings howling.
You want to ask yourself what else did you do when changing oil. And also not what oil went it, but what oil and potential additives came out.
?
In other words, how much molyslip, or ptfe (Slick 50) was also in the oil.
https://www.amazon.co.uk/Holts-GM6RA-Molyslip-Gearbox-Protection/dp/B004R95MCG/
These are OK only if the hardening of the wear surfaces is still effective but clearances have gone up a bit. They will not rescue a worn gearbox or diff.
I used to put Slick 50 in my old (1950s, 1960s, 1970s) engines and boxes etc after they had done about 50K+ and become looser, but modern metals with modern lubricants just don’t need it. My 1994 Astra did 205,000 without touching the engine apart from regular services and was using less oil at the end than when brand new.