Help, split casing, drain plug

Did a gearoil change on my 01 yz 250 2t last week and went out riding yesterday, 10 minutes before i got picked up by my mate i noticed a drip of oil on the drain plug, closer inspection and noticed where the drain plug screws into the casing, one side is solid and wouldnt split and the other side of the threaded hole has got a thin wal and has slightly split probably due to being overtightened and is seeping gearoil :( anyone know how i can repair it in situ without replacing casing? One option i suppose is alu welding..? As i was short of time yesterday i mixed some chemical metal up and pasted that on the split so i could stil ride whilst monitoring the leak, i havnt drained the oil yet to see how much is stil in there?

i think a product like JB weld would seal up the split, but i dont know how long it wil last as when i remove and refit the drain plug it wil possibly make the split worse? I think best would be to scrape the split so i create a V shape in the split and get a alu welder to fil the split chanel with weld and then if needed run a tap through it, without checking the manual i think its a M10 tap, if so i have a set at the ready.....

wel put around 750-770ml in the gerbox last week and done a bit of riding on Saturday then dropped the oil, i got around 750-760ml out, so it doesnt seem to be losing alot? I used a liquid metal type paste and put that around the split and let it go hare...I put around 750-770ml back in around 4o'clock this evening and checked it 10 mins ago (5 hours later) and the clean bowl i put under the drain bolt to check for drips had probably one or two drips of gearoil in it and a little around the drain bolt, so i think if i monitor it regulary i should be ok with it? Its a pain not having a sight glass or level check bolt on the 250 2t yams.. :(