4.4 is a pretty solid engine but like anything aluminum, cooling cooling cooling! One good over-temp and those heads are toast!
Plenty of great options out there that do not need to be factory part and just as reliable for a cheaper buy-in; I'd replace it ASAP if you are seeing signs of failure.
I think NAPA and Oreillys also rent the tools for dirt cheap to pull it and if not I'll send you mine as its a reallllllllyyyyyy easy job to swap the fan!
If you need a video let me know and I'll pull mine off for you and take a video as I just did my water pump again and I'm pretty quick.......lol