2nd gear grind while slowing down NO clutch
 

hi guys, noticed this yesterday and its kinda freaking me out, i always thought my gear box was one of the good ones :(

most noticeable going down a hill, while slowing down in second, foot not even on the clutch. i get a grinding sound as the revs get near 2,200-2,400. I can reproduce it every time, by going on and off the brakes. you can kinda do it in 3rd also.

anyone else get this before?

This a toughy....So it grinds when you hit the brakes with the engine rpm around 2200-2400, or just engine braking at that rpm causes the noise? Tend to think it's not transmission related if your in gear and it makes a grinding sound. Could be just the engines natural resonance in that rpm range when slowing down? Need a bit more information: is the engine warm? Do you feel a vibration/hum while driving? What oil are you using? If your in neutral and coasting what does the engine sound like if you maintained the rpm around 2200-2400 and idle speed?

Edit: what does the grind sound like? Low rumble, high pitched scratchy sound, marble in a tin an sound? Etc.

If it is only happening around a specific RPM I would also be inclined to think it's a resonance with something, like a heat shield. Goind down a hill would hold it a little longer at that RPM while you're slowing down, giving the resonance more time to develop.

Gords questions will help us narrow it down.

Thanks for the replies @Gords_zenith, @wheelhaus.

I'd say it's caused by engine breaking, using the brakes helps recreate it going past those rpms. As for the sound... Yea id probably go with a light juggling of marbles, medium tone, not the worst sounding thing, but definitely noticeable and not healthy sounding.
Engine was fully warm, actually couldn't re create it thismorning when it was cold. Using Mobil 1 0w20, don't feel it just hear it, and only while slowing down.
Haven't tried neutral but other gears don't do it, 3rd slightly but very quiet. I'm gunna play with it but hoping you guys are right and it's just a heat shield or something. Gotta go to dealership soon for pillar rust and window leaking so I'll see if they do anything.

Does it make the noise while sitting still and revving it to 2200-2400 rpm in neutral with clutch out? Then try it with clutch in, and see if it changes anything.

Edit: couple more things, are all your fluids topped up? Have you lifted the hood and try to listen for anything abnormal?

It's not a grind. The noise you're speaking of either has to do with the injectors, or the clutch assembly.

I am inclined to believe it's the dual mass flywheel.

-alex

Okay so oil level and coolant are good, haven't burnt any. And I can't recreate it in neutral, and it's only really that noticeable when going down a hill... I was banging her through the gears today and all seemed well, better than ever actually. It's just that damn grinding at just above 2k when easing to a stop using the engine brake.

I get the light grinding sound from engine braking as well. I think it's from the clutch or flywheel. Only noticeably happens when the car is cold, 30 minutes of driving later the car doesn't make a noise slowing down.

I have a very faint whining grind I might call it when engine braking but it doesn't seem out of ordinary to me. if its easily reproduced id take it in and let a mechanic hear it just to be safe.

Well, I'm not sure of what it could be with out hearing it in person, but if I was to speculate, it might be the clutch assembly rattling a little bit.....at that rpm?!

This has got noticeably worse over the weekend, 2nd and 3rd gear coasting have a metallic milkshake grinding noise between 2-2.5k rpm, only when coasting with no clutch. Seems worst when I go use it when it's partially warm, ie cooling for 30 min to an hour after a 45 min drive then driving around town. It's making me nervous driving it's so I'm gunna tryi to get her into the dealer today, any insight on possibilities before I go would be appreciated, thanks!

Did you solve the problem? I have the same problem in my 2017 brz.

It's just gear chatter/ flywheel chatter. My '16 has had it since day one. Nothing to be concerned with. Just another one of those things you need to come to grips with with this car. Exhaust helps drown out that noise if it bothers you that much.