I am getting a whirring gears type noise, quite hard to describe, fairly high in pitch, that I reckon is coming from the diff, definitely from the rear. It only happens under acceleration (so probably not wheel bearing), more so in lower gears, and especially when accelerating up a hill.
I can’t upload a video on here but I’ve put it here - it sounds a lot clearer in person but it’s the higher pitched whirring/whining noise:
This is my first MX5, so I don’t know what is normal for this car. Is this typical or is there something wrong with it? Thanks
The rear drain valves, on my 2007 NC soft top, can get damaged and act like amplifiers, increasing the road noise
. Thanks to a club member for the picture
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I know they are clear because I have done the drains with the trombone brush, I didn’t notice anything broken when I looked at them. Mine is PRHT but has similar plastic bits.
You don’t actually see that the valve is broken on the inside. Stick a small piece of sponge, 30p from Sainsbury, into each of the drain outlets and see if that makes a difference
I would add that if it hasn’t been done then a change of diff oil is probably in order. It’s pretty simple if you have a way to get under the car and keep it level, just use a GL5 rated oil and a new crush washer. You may as well do the gearbox while you’re under there, too (GL4). It makes a surprising difference
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I read there was a service bulletin from Mazda about the NC diffs before 2013, that there was too much of a certian compound used in the manufacturing that caused them to wear prematurely. The recommendation was to change the diff but that was years ago when they were in warranty. If it’s just noise but there’s nothing actually wrong with the diff I’m fine with that, just want to know if it indicates a problem that needs sorting out.
