DCT sound on deceleration only

[alpinefd]

I'm getting this weird sound from the DCT on deceleration.
The best way i can describe it is like a card in a bicycle wheel spoke.

it only happens on deceleration, and goes way when accelerating.

here's a video, toward the middle is where you can hear the sound very clearly.

Any idea what this could be?

It almost sounds like some kind of chain drive is loose in the DCT

[alpinefd]

the car just had a transmission out DCT oil change, filter change, side cover seal.
and a lightweight fly wheel installed.
but i don't know if this is caused by the flywheel exactly or something else.

[Redd]

It sounds like a loose heat shield to me. Or exhaust pipe contacting a heatshield.

[spammysammich]

if you just had the transmission out, it could be that the tech overtightened the stamped sheet metal nut that holds the transmission shield in place an stripped it to the point where it isn't holding tight or has fallen off. check all your heat shield fasteners.

[alpinefd]

thanks, will check the heat shields as soon as i can.

if it's the heatshield, why would the sound go away when i accelerate.
it only appears on deceleration.

[Redd]

Certain frequencies cause it to vibrate. Also when you decel the weight shift in the drive train could cause something to contact a heat shield momentarily.

[Makaveli7]

The idle sound is probably the headers heat shield - The bolt usually gets loose on the driver side. Check which side is the rattling coming from and follow.

The deceleration sound might be from the middle heatshield touching the driveshaft. I had the same a week ago and this was culprit.

Good luck!

[tigerbalmwoods]

check your heatshield, I had the same problem, my flapping noise was near the back driver side towards the axleback to xpipe connection.

[alpinefd]

I had 2 very good shops go over this, the heat shield all clears.

This only happens under heavy engine braking.
Most noticeably in 2nd gear under 3000rpm (while engine braking).

Any other ideas? Is there such a thing as input bearing for the DCT?

[alpinefd]

the sound is like a card in a bicycle spoke

[Scrippy]

It does sound exactly like the rear center heat shield rubing on the flange of the driveshaft and diff. I replaced my driveshaft a while back and on down shifts I’d hear it. Mine sounded like sand paper making contact on the DS or a grinding. Only on downshifts and never acceleration. With my car on jacks in neutral I could turn my wheels and hear it as well. I just had to pull the aluminum heat shield down away from the DS. Those shields bend very easily and improper storage tweaks them into making fabulous noises like these to scare us. They’re pretty much a more robust aluminum foil and they can be molded as needed.

[alpinefd]

Originally Posted by Scrippy

It does sound exactly like the rear center heat shield rubing on the flange of the driveshaft and diff. I replaced my driveshaft a while back and on down shifts I’d hear it. Mine sounded like sand paper making contact on the DS or a grinding. Only on downshifts and never acceleration. With my car on jacks in neutral I could turn my wheels and hear it as well. I just had to pull the aluminum heat shield down away from the DS. Those shields bend very easily and improper storage tweaks them into making fabulous noises like these to scare us. They’re pretty much a more robust aluminum foil and they can be molded as needed.

interesting... was your sound on deceleration only?

[Scrippy]

Yes and it was very subtle. I thought it was an exhaust leak at first. I have a DCT but I prefer to do the shifting sometimes. It only rubbed 3 to 2 and 2 to 1. Never any of the higher gears.