Help identifying a drivetrain noise

Talk and Tech about turbocharged 924/944/968 cars
duqx
Posts: 8
Joined: Fri Nov 14, 2025 10:31 am
Has thanked: 1 time
hello everyone, I am trying to identify a sound coming from my car

1988 944 Turbo S with 166k miles.

Clutch - 55k miles - 20 years ago
Rear axles - 1k miles -13 years ago
Transaxle fluid - 500 miles - 6 months ago

There is a vibration noise that sounds like it is coming from the middle of the car when I am accelerating slowly at certain RPMs. It seems to happen around 2000 and 3000 rpms. It doesn't seem to happen when I am in gear and engine braking

It doesn't happen when in neutral with the clutch in our out

There is a little vibration in the steering wheel / shifter, but not much

Video of the sound. It is much more noticeable in person than the video shows. Sound happens at 1, 5 and 12 seconds when I give it light gas. I was in 2nd gear during the video



Thanks for any thoughts or suggestions!

#1

duqx
Posts: 8
Joined: Fri Nov 14, 2025 10:31 am
Has thanked: 1 time
SOLVED (I am pretty sure)

I think I just lost focus and strayed from the original issue

When I first started looking into the noise it was a bit higher pitched and would sometimes happen even in neutral. I think I must have tricked myself into forgetting about that part

I started tracking down the noice and it decreased some when I removed the heat shield above the cat

I then dug deeper and saw the exhaust test pipe bracket had broken and that was definitely rattling, so I removed that

After that point the car stopped rattling when in neutral and the sound become lower pitched and more of a growl. I should have continued looking into exhaust issues

I do have a 3" turbo back exhaust with sport cat, and I think that just has much more resonance than the stock exhaust which led to my issues

I pulled the exhaust from the car downpipe back as well as all the heat shields. It was really loud, but it seemed like the nose was gone. I put the exhaust back and and left off the middle two hangers and the noise was gone
I put back in the hangers with some plastic washers and made sure they were super tight.

It is funny that as I am posting this I saw someone just posted a VERY similar issues with vibration around 2k rpm with a 3" exhaust with sport cat

#2

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