If you canged the Radiator and the tube on the old radiator dident leak but leaks on the replacement? that means you disturbed something.
If I remember the radiator nipple for the tranny is a female that requires a male B-nut to draw the tube in.
Are you shure that tube end is a flared type? if so is it double flared? it may have cracked when tightening.
new vehicles a bead and o-ring or the double flare type both which require's a soft steel tubing when fabricating new. when the flare is finished it's still pliable enough to install and conform to fit the nipple face, even on the factory production line radiator nipples have sort of imperfectrion like off center, tool marks, slight seam split during flaring or rolling the bead of the soft tube end, so its still fat, soft and unsmashed helps to seal that gap by conforming to that difference, when tightened that joint is pretty much becomes permant to only that radiator, You'd be lucky if it seals on a replacement, trim it back and roll on a new end. Check the end to see if it was fully seated? or bottomed out? was the line cracked? cracks on steel lines useally follow the seam or is the B-nut cracked?Ive seen this happen on alum and brass B-nuts, on different production runs they had long nipples and short suppose your replacement radiator had a short nipple and the tranny line had a long B-nut that may allow leaking.
