Grinding noise on deceleration

[andi42]

Hi there,

I have been noticing a strange noise after driving the car for a while on city traffic. It only happens on deceleration from 2000-15000 rpms but only when the car is warm. So when I got i checked from a mechanic, they didn't had a chance to hear the noise at all. 

It's a corolla e12 1.4 d4d, with a mmt gearbox,150k miles. I just changed the oil and filters. During the inspection, found out that the alternator pulley freewheel wasn't working so I replaced that hoping that the noise was caused by that. A few traffic lights later it was doing it again. 😥

I am still not sure if this noise is belt driven. Should I replace all the other pulleys (ac pulley, water pump) and just see if this would fix the problem?

Could it be gearbox related? If so, is there a way to test this?

Thanks in advance.