I am doing this big job right now on my 4.5. I have the AC out for renovation anyhow and I need to rebuild the ventilation before I bring the AC back. I saw that all foam seals for the vents are gone and the heater fan is questionable. So it is time to tacke this.

Now I have everything disconnected/removed around and the heater box is lose. I can pull the heater box back as far as possible but barely get the 2 copper pipes through the fire wall, only with force. I am afraid I'll damage something.
There is just not enough slack that I could free up that box through the fire wall.
One unknown to me is what happens with the heater fan. Is this fan connected to the heater box? Does it come out with the heater box or is this an independent unit that stays in place while the heater core is removed.

Main question is how to get the heater box out there.

Thanks for any hints. Martin