I don't think they sell JB Weld in 55 gal drums. At least not were I work at Lowes.
JB weld is good stuff but not structurally strong enough for that job.
The Tranny would have to be removed and squeezed together.. IMHO. we have enough problems with the stock tranny and that would not help.. REPLACE it with a 4:44 . Consider it an opportunity not a problem. Good luck