Very normal timing. Yes it's a drain and refill. Only need a 3/8th ratchet, muscle and a way to funnel new fluid into the top bolt hole. Also new crush washers
Are you able to use this method by yourself (no helper) without making a mess? How do you keep the tubing in the differential and know when to stop pouring the fluid in the funnel without overfilling? Do you just pour a bit at a time and keep checking?
So it takes a little more than 1 qt. So if you get all of the first bottle in safely without spilling, when you start pouring the second, you just wait for it to spill into the drain pan and stop pouring. You could go slower on the second quart and do it by yourself easily.
I actually have one of these and haven't had very good success with it. I've tried to use it to drain the fuel from both a generator and a snow thrower and the pump never seemed to develop enough suction. I've had better luck with a Pennzoil Siphon Pump.