Earlier Today you wrote that plastic around where tranny line goes to radiator was brittle /broken and this is where leaking was occurring. However as this is area/side where there is tranny fluid not coolant I am confused. If anything your leak should be tranny fluid in this area not coolant. This is not good either but better then coolant leak. However whether a tranny fluid leak or coolant leak if you are certain that leak is at radiator then you should pressure test radiator and repair/replace it if it is defective. If you are sure it is coolant leak and are sure it came frome tranny area of radiator then probably coolant has gotten into/mixed into your tranny fluid. Change out defective radator and do tranny fluid flush/change. If coolant got into your tranny fluid that is a bad thing and could damage tranny . Hopefully you caught it in time before damage occurred and flushing/changing tranny fluid will get rid of bad/contaminated mix. Good luck.
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' 86 manual sedan nearly 210,000 and ' 87 auto sedan nearly 125,000