leaking transfer case vs. Blue Devil oil stop leak product

[Petesexpy]

The transfer case in my 2000 Expedition LTX has been leaking for 10 years, but the repair would cost as much as a remanned new transfer case. My question is if anybody used the Blue Devil oil stop leak on a transfer case? The write up lists "gear cases" as one of the uses, but I do not want to make the leak worse (I only add a quart of ATF a year) or damage the case.