Strange Noise Between Gears - Need Help With Diagnosis.

[jackbh241]

Hi Guys,

 

I'm new to the forum and I'm trying to sort out an issue I'm having with my manual 89' Corolla AE92. I'll admit this car has been abused since I've owned it and has been driven way too hard (and I'm regretting it now haha). Anyway, the noise is a loud grinding noise that is most obvious when I'm accelerating reasonably hard and then go to shift to the next gear (aka the sound is most obvious between gears with the clutch in, but not necessarily when just revving in neutral). It does present itself during general acceleration (particularly in second gear) but it is usually not too noticeable especially if I'm driving sensibly.

 

The best way I can describe the sound is a metallic grinding that is sometimes reminiscent of a blow off valve in the way that it starts off loud/fierce and decreases in volume/severity rapidly.

 

Any suggestions as to what it could be would be greatly appreciated, I will post an audio clip if necessary.

 

Thanks so much.

[7shades]

Possibly thrust/throwout bearing.

[jackbh241]

hey thanks for the help. quite possibly. I had a look around the internet and it could be but I still couldn't find a sound that matches.

 

I also realised it also makes the noise when you are just revving the engine in neutral and it sounds like it comes from underneath the car?

 

I uploaded a video of the sound, it's a little hard to hear but it is the metallic sound that you can hear after each rev.

 

Let me know if you have any other thoughts. Thanks :)

[jackbh241]

sorry forgot to post the link: http://www.youtube.com/watch?v=tEtnG58TeYU

 

(and ignore the whistling I'm pretty sure that's just a vacuum leak somewhere but is a different issue entirely as that's been there since I bought the car two years ago)

[7shades]

That sounds more like a vibration/rattle... Exhaust heatshield or something....

 

Try slowly bringing the revs up from idle until it makes the noise... And hold it there.

[altezzaclub]

So it is independent of you using the clutch actually?? You get the noise with the clutch up in the video, not just changing gears?

 

So its not particularly clutch related, its a deceleration vibration- something in the exhaust??

 

Some loose thin plate that rattles when the motor tips to its over-run position, but is clear when the motor tips back to its acceleration position?? Exhaust cover? gearlever linkage? undertray? engine or gearbox mount? flywheel cover?? Go over all the nuts & bolts and smack all the panels you can find.

[jackbh241]

Hi. Yes, sorry i corrected myself a few posts down, it appears to be independent of the clutch as it happens with the clutch out or in. However this was the only situation that I could get my camera to pick up the noise, it also does it when in gear and revving hard(ish), dropping back to a low gear etc.

 

Cheers though, I'll get under the car and have a tap around. Thanks :)