Stop-leak additive for transfer case?

My NP242 has a blown rear output seal that has been holding on for a while, but is finally starting to really spew. I don't drive the jeep too much, but I have around a 700km drive to make in a few months, and since it'll be winter I won't really want to crawl under the rig to top up the fluid on my way. I'm wondering if I can add some kind of a "stop leak" fluid to the transfer case to try and slow it down. Once I'm done the 700km drive I have access to a heated shop and more tools, so I can replace the bushing and seal then. I have some lucas oil additive sitting in my garage that says it "stops leaks". Would this be safe to use in the transfer case with the fluid, or should I try using a transmission specefic stop-leak for the time being before I can get to replacing the seal/bushing?
If it's too risky to add additives, I'll just make sure I top up the fluid every now and again.

Don't think I would be adding anything other than atf to mine. I understand your weather issues, sometimes I just have to throw on some gear and get nasty, cold and wet to fix mine. Sorry I don't have any other fix than the prescribed one.

i really dont know anything about it but logicly it seems less risky to put additives in a box of spinning gears and a chain than it would be to put it in a hydryaluic pump ie: the tranny old dealer trick is to add a spoonful of brake fluid to swell the seals