Welcome.
Can I presume that you are working on a '94 or later LT with ABSII?
Yes, you can do the job without removing the ABS pump/controller, I have done it both ways, and believe me, it is much easier to remove the transmission without that ABS controller hanging in the way.
You only have the multi-pin plug on the front side, and 4 wires in the wiring box. The cover of the box can be removed, though it is intended to be a "single" use cover, you can re-use it so long as you seal the "hole" you have to make to remove it.
I think there are some pics here on this forum that show the cover and where the hole needs to be to remove the cover.
Other than this little bit of wiring, it's then just 4 brake line connections, and a couple of mounting screws. You do not need to remove the electronics part from the pump part, it can stay as one piece.
Here's an image of the "catch" that keeps the cover on. The cover slides vertically up to remove.
