Term taxonomy child from first and second level menu
I've found a way to do it. It's not the best way but it's a way which is enough clean for me for now .
It's with Menu block module.
I made 2 blocks with this module and I configure it on a specific page.
http://www.youtube.com/watch?v=1rku2vHqZP4

If you want you can also use Pathauto module to generate nice url so you don't need to configure  on evry specific page but on every page with a specific URL like www.yoursite/Vehicle/*.

To configure that go to admin/config/search/path/settings and set the Slash (/) option to "Do not Replace" under "Punctuation" then go to the taxonomy path which you need and put [term:parents:join:/]/[term:name] the URL will be like www.yoursite/Vehicle/4-wheel/car.

Hope that help.