you really don't want to use jb weld for thread repairs ,jb weld is
great for repair work for patching holes and for holding some light
weight brackets on, but for making threads it wouldn't be the best since
the threads will actually fail it isn't designed for holding that kind
of pressure that threads apply or the bolt will never come out again
which isn't good either ,now to actually do the job right and look
professional you can either drop the tranny down enough to get a drill
in to install the helicoil or remove it completely and the last go buy a
right angle adaptor for your drill or a right angle air powered drill
this is angled at 90 degrees to fit in tight places and is a great
investment ,but another idea you could do is since you stripped out the
hole is take the next size tap and tap out the hole the go get a piece
of aluminum rod and drill out the center and tap it then cut it to
length to fit flush in the tranny and helicoil it and get a lil longer
bolt with the correct thread size and put a nut on the bolt and put it
in the rod and part way and tighten the nut against to lock it in place
now proceed to use a die and make threads to match the over size threads
of your tranny on the outside of the rod once the threads are done coat
the outside of the rod liberally with loctite and then using the bolt
thread it in the hole til snug and then let it sit for a few minutes
loosen the nut and remove the bolt and you just done a repair that will
probably out last the tranny itself ,if you get a higher grade of
aluminum then the cast aluminum case you may not even have to use a
helicoil at all in the threads ,just don't use stainless hardware in the
aluminum threads it will corrode it use the stock hardware
good luck