Cobjones

I had this same knock. Only at idle. Turns out it was the flywheel going bad... Took the shop 2 hours to find out what it was.

Sirikenewtron

They finally ended up changing my torque converter but before they did it destroyed another bran new engine so they had to replace the engine a 3rd time.
​​​​​​ After about 500 miles on this newest engine and new torque for the sound has very slightly come back but it's extremely hard to notice and hasn't gotten worse with more miles like the other times (knock on wood)

Cobjones

Mine started as a slight sound 2 days ago. Then today it was loud.

Sirikenewtron

That's how mine was too on my last couple engines.. Just got pretty loud all of a sudden like in the video. And what eventually ends up happening is the wobble or unbalanced of it causes issues with the main bearing, basically ends up pulverizing them

Cobjones

Let's hope the flywheel is the culprit on mine.

Sirikenewtron

Was it?

Nathan13/3.5

Same issue with my 2013 3.5.
Trans temp needs to be above 130.
At idle up to 2000 rpms.
Neutral or in drive. Doesn’t matter.
Occurring intermittently.
Also will experience a grinding sound and vibration or resonance when decelerating from 3rd gear down to a release moment just before full stop.
Both issues will not occur at the same time.
It’s one or the other or she runs fine.
Trans temp seems to be a consistent factor.
Feels like a converter / fly wheel issue.

Curious to figure this one out!
Quoted $1000 to gamble on converter.
Nive to meet you all!

Sirikenewtron

Well if it makes you feel any better as far as the drum on a bucket sound I just bought a 2019 f150 3.5 and it does the same thing, just like my old 2013 3.5 did.
I also test drove 3 other trucks and out of those 3 9ne other did it too, all 2019's and bran new.