Idle chirp and shifting issues

Technical Area Engine, Transmission, Exhaust etc
1
  1. My model of MX-5 is: 2019 MK4 RF 2.0
  2. I’m based near: UK
  3. I’m looking for technical help or recommendations on: Clutch / gearbox issues

Had a couple of things start to feel not so good on my ND lately and need to start diagnosing the problem.

Most obvious is a high pitched chirp which I can hear at idle, which goes away when the clutch pedal is even slightly depressed (like within what I assume is basically free play before it starts to actually disengage the clutch).

I also started to experience some problems getting into gear. This is intermittent, and ranges from just a stiff feeling sometimes, to having issues getting into gear when shifting at high revs / speed, to the most noticeable symptom, which is when I am occasionally unable to shift into first at traffic lights. I never have any issues getting out of gear, nor when in gear.

It’s really hard to actually say exactly when everything started to happen or if it is connected, as mentally I am kind of trying to relate them even though they may be totally unrelated. I started noticing both not long after having my brakes replaced, though.

On the chirp, I’ve read that the best place to start is probably by lubricating the clutch slave cylinder push rod where it meets the clutch fork, to rule that out. Though I know what I’m looking for, I cannot actually see it looking through the engine bay, nor through the drivers wheel arch. Any advice on how best to access it?

On the gear changes, does this sound like wear and tear, failing gearbox, or something more specific, maybe related to the clutch? The car only has around 30k miles, but I am not exactly gentle with my gear changes, With that said, this is my third 2.0l MX5 and I have had zero gearbox issues in the past, even past 100k miles…

EDIT: happened to notice a new symptom driving the car this afternoon - on two occasions, when I engaged the clutch (lifted off) the pedal stopped half way through it’s return, then popped the rest of the way… I could feel it strike the bottom of my foot! This is leading me to believe there is some problem with some part of the clutch…

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I would start by bleeding the clutch. Does pumping the clutch pedal before changing gear make things better? Have you done a gearbox oil change?

You do not say if this is your third ND. The gearbox in the ND is not the same as previous models so comparison is unwise.

The resident harbingers of doom will be along shortly!!
:heart:

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Hi Malc, thanks for the response. Yes I appreciate the ND is a different car, and my previous were NCs. I guess I just wanted to express that I shift briskly, but I’m not in the habit of destroying gearboxes!

I actually did get the gearbox oil changed, as the brakes needed doing for the MOT, and the oil was IIRC specified in the schedule for that service, so it was done after I started noticing symptoms. The oil change made no difference so far as I could tell.

I did wonder if bleeding could be the issue just because it could’ve been missed after the brake work. I don’t have a pit, ramps, or even a jack currently so the work I can do myself is extremely limited unfortunately, but I will ask to have the slave cylinder bled next time it’s on the ramps. Thanks for the advice.

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The whirring sound on idle, which goes when you put the clutch pedal in, then returns when you take it off, has been documented a number of times. There was even a TSB when users complained when it occurred on the NC too. Rollover noise iirc.
Mines done that pretty much from the get go. Touch wood nearly 7 years on it’s exactly the same. I got paranoid when I first mentioned it on some other forum years ago. I was told the sky was falling in and basically to check life insurance. I tried 2 different cars in dealerships, one a demo, the other newish too (from what I can recall). Both did the same. I even asked about 3 people in car parks over the ensuing months to demonstrate their’s. They all had it too. The only one I didn’t hear it on was a Sports Recaro who’s owner I was talking to a few years ago, parked up in a park I was with with my dog.
A few others on here have commented on it too. A few on youtube as well. I got a dealer to listen to it on a service in March '20, and he said it’s a rear wheel drive thing. Soundproofing. I can’t recall. I expected to them to say something like that obviously, but still.
Gears? Mine is ok, touch tood. Was stiffer for the first 5K miles or so from new. I think the 'box is overrated by reviewers though in terms of being ‘magical’. My up! gti got a shift dreams where made of, and it’s always harder work (but not in the something wrong with it sense) when I drive the ND after that.

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I would really hope it’s not normal, it’s quite loud, almost like a belt squeal. Also never had it on the NC. Could certainly be unrelated to the shifting issues though, so if I find a fix for that, and the chirping continues, I won’t be overly concerned, cheers!

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I’d probably look at re-bleeding the system, as Malc says above.

The brake and clutch systems share the same fluid reservoir, so the fact you’ve started noticing this issue after works on the brakes might not be coincidental.

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Thanks for all the suggestions. For anyone else struggling with this issue, to cut a long story short, I bit the bullet and had the whole clutch replaced, and the plate that came out was shredded in a way I have never seen before! I have had clutches wear out, but usually they slipped before failing, and the fact that this one did not really threw me off.

Lesson learnt, the ND2 clutch and engine combo does not like the way I have been driving the car!