Hey i would like to know what will his female name is if he turn into a girl.

You could go with Echo, that would kind of fit the name.

Rumble, probably referencing the sound of thunder and a series sounds.
Echo, most feminine sound related word I could think of and it makes sense as it means "a sound or series of sounds caused by the reflection of sound waves from a surface back to the listener." which is close kinda close to rumble... Maybe if you squint.

3135979 i think i can go with that

3129570

Frenzy.

But seriously, I think Rumble works either way.

3153061

Frenzy.

*Insert "I see what you did there" joke*

It could still be Rumble. It isn't really a name bound to a specific gender.