Knocking noise coming from gearbox under accelration

[ciciban]

Hey guys,

I've been experiencing a rather concerning issue with my 2007 1.4 manual Jazz and I'm hoping to get some insight from the community here. Whenever I accelerate hard, particularly in 1st, 2nd, and occasionally 3rd gear, I notice a knocking noise occurring between 2000 and 3000 rpm. Noise doesn't occur when driving in reverse. My mechanic suspects it might be related to the gearbox.

I'm aware of the infamous input shaft bearing noise that's common in lower gears. I've had that noise since I bought the car. But this knocking noise during hard acceleration has me a bit worried, especially considering the mileage on my car, which now stands at 170k kilometers (105k miles).

Has anyone else encountered a similar issue? If so, what was the root cause and how did you address it? Any advice or suggestions would be greatly appreciated.
Thanks!

[Lord Voltermore]

You could  check engine mounts for any sign that hard rubber has  deteriorated allowing too much engine/gearbox  movement .  Hard acceleration  increases how much the engine /gearbox tries to twist on its mounts due to torque.      Rubber bushes etc can deteriorate due to the age of the car ,not just kilometers driven. 

This is only a suggestion. I am not a mechanic and have no prior experience of  Jazz mechanical problems.