Single knock/clunk on startup/gear change

Hi Guys,

I have been searching the internet and I find it strange that I haven't been able to find a thread where someone has a similar problem to me. Usually most of my issues are covered in other threads, maybe I'm just no good with the search function.

I have a BAM S3, and when I start up the car, around 50% of the time there is quite a noticeable clunk as if something has gone slack and then suddenly pulled tight when the engine started. I really don't know how to describe it better than that. It is only a singular "clunk" when the engine fires into life. I start the car with the gearbox in neutral and the clutch engaged if that matters.

Also on gear changes (mainly first to second, sometimes second to third) there is quite a clunk when I disengage the clutch to go to the next gear. This is usually under very light throttle.

I have replaced the top two engine mounts with Vibratechnics and poly'd both bushes in the dogbone. I notice slightly more vibrations in the cabin and smoother acceleration on and off the throttle but sadly it hasn't fixed my issue.

The gearbox also whines a bit in second gear, if that is related at all..


I would appreciate any help, thanks!


On a side note, I am spending part of the weekend making a budget catch can that may interest some a3/s3 owners, I will post a guide up hopefully tomorrow when it is complete! This community has given me a lot of advice and help so I want to try my best to contribute back!

Thanks for the reply guys. I have replaced both bushes in my dogbone engine mount so it shouldn't be that.

I'm thinking that the clunk I get whilst driving could be my nackered suspension bushes, I guess I'll have to wait until I change them. But this wouldn't explain the noise when I start the car.. And I'm not sure if they are related or not

Just an update guys. Changed all my suspension bushes, so the majority of the car has entire new mounts and bushes, but the knock is still there (maybe not quite so bad). I notice it mainly when I change from first to second and then when I downshift a little aggressively from say 5th to 3rd to overtake someone. If I accelerate in first gear, take my foot completely off the accelerator for a second and then press the clutch in, I DON'T get the noise. But if I keep my foot on the accelerator very slightly to make the gear change as smooth as possible, I get the clunk

I've noticed that the clutch getting pretty tired, could it be the clutch or flywheel making the noise? The best way I could describe it, is as if two pieces of metal are "clapping" or knocking together.

Any ideas as to what it could be would be really appreciated!

edit: my top mounts haven't been changed on my coilovers, but when I fit the coilovers they seemed to be in good condition.

I'm hoping it's the flywheel, because I have a new one waiting to be fitted (when I can be bothered )

could someone please confirm if a flywheel can make the noise I'm describing?

My dad's buying a hoist so I'm going to wait until that arrives before I fit it. Also to me, changing a clutch is a big job (I've never actually done it before).

So before I change the flywheel and clutch, I thought I would post the question in case it's something else, which could potentially be causing damage. Also if a knackered flywheel makes the noise I'm describing, I'll be relieved to know what is likely causing the noise