240 Jet transmission - Fill/vent screws stuck

[Hawk111]

I am planning to change my transfer case oil on my Challenger M2 240 jet pump. I found the two screws and I have all the knowledge on what to use etc. my big problem though is that the drain and vent plug are stuck/ corroded in place. They won’t budge. Who ever thought a flat head screw drain plug was a good idea? Seriously? Not only are they stuck but now the flathead plugs are stripped out on top.
I could drill a pilot hole and then use the screw extractor bit - but those break sometimes. I think the transfer case, that houses the 90 degree pinion, is made out of aluminum. Only other choice is to weld the screwdriver to the top of the plug and hope the aluminum doesn’t disfigure or melt. What should I do? I simply just want to know if there is still oil in there, but there is no sight glass or way to check the level. I can see why they stopped making these. I am probably going to go with welding the screwdriver to the plug and hope for the best. I’ve seen tutorials of guys doing stuff like this, using wax, map torch etc. anybody ever try this?

 

[Tim75]

The typical reason those plugs get stuck (corroded) in place is they were not checked yearly.

Are you using the biggest blade you can get into the slot? I had to put a scissor jack under a wrench to keep the blade from "camming out" of the slot. Can you use a Dremel cutoff wheel to make a new slot in the screw?

If you can TIG weld a screwdriver blade onto the screwhead, you should be able to get them out. Maybe tig a nut onto the screw. The screw/plug are common on outboards.

 

[Hawk111]

The typical reason those plugs get stuck (corroded) in place is they were not checked yearly.

Are you using the biggest blade you can get into the slot? I had to put a scissor jack under a wrench to keep the blade from "camming out" of the slot. Can you use a Dremel cutoff wheel to make a new slot in the screw?

If you can TIG weld a screwdriver blade onto the screwhead, you should be able to get them out. Maybe tig a nut onto the screw. The screw/plug are common on outboards.

I could try the Dremel cutoff wheel, but it would have to be halfway worn down to fit on screw head. Even so, probably not going to try that. I’m thinking I’m going to flux core weld it on - on the seem of the flat head screwdriver meeting the screw. Definitely was not checked yearly before me. Couldn’t have been. I’ve heard the story of people impact driving it in. This could have been done, but definitely not in the past five years. I’m wondering if ever actually. My engine has a slight sputter (like a skip or slight acel) to it occasionally when in neutral. Makes me wonder if it’s just a little surge in fuel or throttle vibration or maybe it’s actually skipping teeth on the 90 degree pinion gears. As for the screwdriver head, I had to make a screwdriver that would fit by grinding one down to make it bigger. The biggest one at harbor freight was not big enough and it was big. Anybody have any other advice?