Hi there,
I also have vitz 2005 new shape, I used to get this Tuk sound from the front part of the car on breaking and also while changing the gear from R to D and D to R.
Turns out that the axle was slipping or whatever you call it, changed the axle and the sound went away.
@vitz_2006 is the issue resolved now, please let us know what was the cause. Thanks