Knock noise when coming off throttle at slow speeds

[Chang]

Hello,
I’ve got a b8.5 A4 2.0 TDI quattro with a S tronic

I’ve noticed it a lot more recently, when pulling off or coming off the throttle as slow speeds eg in traffic I hear a knock sorta noise, I have a suspicion It could be the gearbox mount under the car and was thinking of trying one of them inserts to see if that stops the noise, because to me it feels like the gearbox is moving when load is put through it. I’m not 100% sure it is that tho, and was wondering if anyone else had this before?
Also sometimes it happens when putting it into gear, the car drives perfectly it just bugs me like hell.

Thanks!

 

[Nitro_CR]

It isn't a rattling noise like a bike chain freewheeling is it?

 

[Chang]

Not quite,
Even driving with music loud you can still feel it,
It feels to me as if something is moving under the car.

thanks