I’m looking for technical help or recommendations on: Transmission noise
When I accelerate in any gear I get a sound akin to driving over gravel or a grinding sound. Only occurs on acceleration, not coasting or deceleration. It also doesn’t occur if I rev the engine from idle (Although it does sound a like a diesel engine at idle).
I can kind of minimise it if I accelerate slowly in a gear(Can still occur, just less), however if I do a quick firm press to the floor I get this sound. The only other thing related to this is that the shifter is really stiff moving between each gear, so I am going to change the transmission and turret fluid soon. Has anyone had something similar and if so do you know what it was?
You say it sounds like a diesel engine at idle? Check the aux belt tensioners, if you’re pretty sure that’s not the area of the noise then of course the gear oil change sounds a good idea, diff oil too.
I think I am experiencing a similar problem in my 2010 NC, occasionally from a stand still it sounds like there is some gravel/stone noises coming from the rear of the car, I was planning on changing my diff oil this/next weekend and then the gear oil the following weekend as the vehicle is due a change and I’m not sure if a previous owner has done this.
Hopefully that should fix it I will report back if it goes away with either change.
You say it sounds like a diesel engine at idle? Check the aux belt tensioners
Checked the tensioners, nothing squeaks or is noisy, however recently the car is having a harder time starting like it isn’t getting enough power. I think the alternator might be going, but I am not sure if that is the source of the noise because I would have thought it would be constant throughout driving, not just acceleration.
Could it be a noisy release bearing?
The actual disengagment and engagement of the clutch there is no noise, it is only when I accelerate. So I don’t think so but I could be wrong.
I think I am experiencing a similar problem in my 2010 NC, occasionally from a stand still it sounds like there is some gravel/stone noises coming from the rear of the car, I was planning on changing my diff oil this/next weekend and then the gear oil the following weekend as the vehicle is due a change and I’m not sure if a previous owner has done this.
I was going to change my gearbox oil this weekend and the diff oil the weekend after if it doesn’t improve. Hopefully the problem is just a dried out gearbox being hot and noisy.
To add to that unlike yours my car does not sound like a diesel at idle. So it could be something different or two separate issues.
From what I can find on the forum and other sites this was because I had my AC on in idle, seems to be a little quirk with the mx5.
If the universal joint bearing at the rear of the prop shaft dries out, the needles in there can sound very rough, like crunching gravel.
From what I can find this would be a constant noise, not just on acceleration. I think I will have a look under just incase though.
So I figured it out, turns out it was no longer present when I turned off my AC. I need to get it looked at, but I think the problem was it was regassed just before I bought it and it was overfilled, therefore the compressor was struggling.
Reminds me of this rather long thread on Miata.net titled, I didn’t know that I bought a diesel!!
Yup, that was the page I found. Kind of annoying really, when I have the roof down at a stop light with the AC on it sounds like a truck engine. Still worth it for the car as a whole though.
Turns out that the AC wasn’t the problem, but it increased the load on the engine which made the sound more noticeable. There is a squeaking sound from the front of the engine when idling, which makes me think that the aux belt tensioners are actually to blame. Can anyone point me to a reliable mechanic near the Braintree/Chelmsford area that would be able to diagnose it?
Diagnosed by removing the serpentine belt and restarting the engine for 30 seconds to see if noise has gone ??
Replace all pullys and belt if so .
Easy job
See YouTube
