Will I need to remove the transmission?

Bell housing from a chevy 350 engine to replace the rear freeze plugs? Not my truck, helping a friend. The truck is leaking coolant on the passenger side and it is running down the bell housing and the starter on the pass. side. Not 100% sure it is the freeze plug or the head gasket leaking. We are trying to locate the leak before we pull the engine from the truck.

So is it possible to replace the rear freeze plugs on a 350ci chevy engine without removing the transmission? Or does the bell housing cover up the rear freeze plugs? His truck has a 4 speed auto possibly a 4L60 or 4L80 series transmission.