Empty 727

The 727 in my truck blew the front main seal a while back. I am about to overhaul the engine and fix the tranny but I've run into a small problem. I had the tow guys park my truck at the top of my hill. I need to get the truck down the hill to work on it. I was planning on just starting the truck so that i would have power brakes, putting it in neutral, and rolling it down the hill. However, i just remembered that while in neutral the tranny will be trying to pump fluid. How much damage will i be risking by having it empty and in neutral for about 5 minutes or so. Or will it not matter since I'm not trying to drive the car? Any advice is appreciated as I hope to begin this evening.