My girlfriend just bought a manual 2012 Ford Focus and I tried it first because she didn't know how to drive with a stick yet (only auto). However, I was a bit struggling when shifting between first and second gear (it wasn't super smooth) because I am used to my car. My car is a 2004 Toyota Matrix and the clutch has a really high engagement point, compared to the Focus where it is much closer to the floor (lower). Also, the Focus clutch is really soft and light (more reactive and nervous), while mine is much stiffer and heavy (takes some time to come back to initial position if dropped).
So, I decided to rev it up a bit to try it. I went to about 5-6k on first gear and that was fine, but when I shifted to second and released the clutch (too quickly I think), it did a big and loud "TOCK!", just about the same sound as when your suspension hit a big hole on the road. She was like "what the heck" and me too, so I didn't tried it again. After this moment, I noticed nothing wrong and everything was going just like before it happened.
Any idea on what did this sound? Are there some parts that could have been damaged? Thanks.