904 Transmission 1-2 shift control valve spring install help.

Once you see the valve body as shown in the picture above it's obvious and super easy.
Slide the valve out and swap springs, slide the valve back in and re install the small section you took off to get to it.
Ok so to take that portion of the valve body out I'll need to drain the fluid, drop the pan, then unbolt that section of valve body? I'm really a noob when it comes to internals of transmissions.