Not today, but recently switched out transfer cases. Mine started making a loud clicking noise which then became a popping at moderate acceleration while 4wd was engaged. Had no power at the front wheels either. I used the troubleshooting guide to determine that it was the transfer case. Then I went to the yard and jerked an HD case out of a TB EXT.
$150 and two hours later, I was back in 4wd.
I've sourced the parts, and while it's a bit cost prohibitive (since I can get t-cases for $150), I don't want to swap out t-cases every couple years, so I'm going to do a complete rebuild, clutches and all, as I get the cash to buy parts. Judging by what I've found, I should be able to do an entire rebuild myself for around $500.
Bravada G80 3.73 converted to selectable 4wd.