Brief rattle when getting on the gas at specific RPM.

[DaBoBo21]

Originally Posted by cat94

I guess rattle isn't really the best word, but it definitely sounds metallic, and not a normal souding buzz.

I find that when the sound does happen, and I'm rolling onto the throttle gently the sound is actually louder. However, it is easier to reproduce when jabbing the throttle.

This is a clip of my BRZ from over a year ago. Excuse the exhaust, but is this the noise you're referring to?

[cat94]

Originally Posted by DaBoBo21

This is a clip of my BRZ from over a year ago. Excuse the exhaust, but is this the noise you're referring to?

Not quite, it sounds exactly the sound in this video 1:00 & 1:40.

[DaBoBo21]

Originally Posted by cat94

Not quite, it sounds exactly the sound in this video 1:00 & 1:40.

I can faintly hear it at the 1:40 mark, but I'm not sure what that could be. Sorry!

[Bonburner]

Isn't that the sound of the LSD?

[Jordanwolf]

Originally Posted by cat94

Hello,

I have a 2017 stock 86, and I've noticed in the last couple of months a rattle that's starting to concern me.

When cruising at around 2.5-2.8k rpms completely off the gas, the moment I start accelerating there is a brief (<0.5s) metallic sounding rattle/grinding noise. The sound is louder when the windows are down. Also, it doesn't always happen. Sometimes it is extremely noticeable, and I can consistently reproduce the noise. Other times it is very quiet, or doesn't happen at all.

Every gear will cause the rattle, but I've noticed that higher gears are worse. My guess is because higher gears take slightly longer to leave the RPM range of the rattle.

I'm planning on taking the car in under warranty for a squeaky clutch, and want to explain this problem too. Has anyone ever experienced something like this?

This sound exists in every single 2017+ manual 86/BRZ I have driven. Toyota Canada, as far as I know is deeming this a non-issue until further....very, very casual investigation finds it, or a customer can pinpoint the issue with evidence.

Source, going to Toyota basically since I've gotten my car over and over and calling head office over and over.

[Tristor]

From listening to your video, it sounds more like a crunching than a rattle. Does it feel different when it occurs as well? Sounds like it might be diff or gearbox... but I'm not sure.

[RZNT4R]

Originally Posted by Jordanwolf

This sound exists in every single 2017+ manual 86/BRZ I have driven. Toyota Canada, as far as I know is deeming this a non-issue until further....very, very casual investigation finds it, or a customer can pinpoint the issue with evidence.

Source, going to Toyota basically since I've gotten my car over and over and calling head office over and over.

Nice to know they're waiting for me. I'm not in a huge hurry, but I'll find it.

Originally Posted by Bonburner

Isn't that the sound of the LSD?

How do you think a torsen lsd works?

[626reppin]

Originally Posted by Jordanwolf

This sound exists in every single 2017+ manual 86/BRZ I have driven. Toyota Canada, as far as I know is deeming this a non-issue until further....very, very casual investigation finds it, or a customer can pinpoint the issue with evidence.

Source, going to Toyota basically since I've gotten my car over and over and calling head office over and over.

I just found this thread. My 2018 Toyota 86 has this noise as well

[Bonburner]

Originally Posted by RZNT4R

How do you think a torsen lsd works?

[ame]https://www.youtube.com/watch?v=JEiSTzK-A2A[/ame]

Quite a bunch of spinning gears for a potential for brief rattling when spur/worm wheels when suddenly locked?

[RZNT4R]

That's a torsen type a that does have a bit more gear lash than the type b used by the 86, but it would never be this loud, heck, a G80 locker isn't this loud

[Bonburner]

Originally Posted by RZNT4R

That's a torsen type a that does have a bit more gear lash than the type b used by the 86, but it would never be this loud, heck, a G80 locker isn't this loud

we have no sound deadening besides 1 pad on each side of the rear quarter panel. I hear rock rattles in this car. I hear the transmission gear rattling, why not the LSD rattle?

[ame]https://www.youtube.com/watch?v=5WdySzQtSSA[/ame]

Ultimately same situation. Gears in standing motion until sudden input causing adjustment in torque transmittance which may be causing the rattle.

At least for me, that's the direction the noise seems to be coming from.

[RZNT4R]

Originally Posted by Bonburner

we have no sound deadening besides 1 pad on each side of the rear quarter panel. I hear rock rattles in this car. I hear the transmission gear rattling, why not the LSD rattle?

Ultimately same situation. Gears in standing motion until sudden input causing adjustment in torque transmittance which may be causing the rattle.

At least for me, that's the direction the noise seems to be coming from.

If you'd've been reading what I posted, you'd know the sound is resonating in the engine block because I've been using a DSO on the knock sensors to pick it up.

If you're telling me rattle from the gear lash in the diff isn't getting lost in the super soft diff bushings, is making it's way up the driveshaft, through the transmission, through the sprung clutch hub and is showing up on the knock sensors clear as day,



Fine, but do more than just throw the idea out there, test and investigate. At least I'm doing real tests to find it.

[Bonburner]

Originally Posted by RZNT4R

If you'd've been reading what I posted, you'd know the sound is resonating in the engine block because I've been using a DSO on the knock sensors to pick it up.

If you're telling me rattle from the gear lash in the diff isn't getting lost in the super soft diff bushings, is making it's way up the driveshaft, through the transmission, through the sprung clutch hub and is showing up on the knock sensors clear as day,



Fine, but do more than just throw the idea out there, test and investigate. At least I'm doing real tests to find it.

1) I don't have interest in purchasing equipment for something that I think is not an issue

2) my results would hold little value as my vehicle is not the same as your & equipment would be different - my results would be moot to you with various confounders.

3) you could easily slap on your sensors near/on the diff and check the peak sound wave oscillation. If its higher/highest near/on the diff, you're closer to the source.

4) dif bushings aren't as soft as you're putting it; if the sound is able to reach your ears, those very vibrations would be able to be picked up in the engine which is connected by solid metal pieces (vibrations travels better through metal than switching through air, metal, air, fabrics, and whatever materials it goes through to get to your ear)