Black Foam???? Is this Permatex that was put on to seal the shifter to the housing? If all the threads are there I guess it will be OK, but can you get a picture so we can see it. I am not a fan on JB WELD but if you think you can do that to build it back up then try it. I personally would tear it down weld it up on my Tig Welder and drill and tap the hole again, but I most likey would have to dis-assemble the tranny, to properly weld it up. The case would need to be heated then welded cast aluminum can be tricky at times.
I have done the driveway swap of the tranny, I bet that gravel is a PIA. What I do in my garage is jack it up as high as I can get it then I install the cross member to the tranny, I tape up the shifter hole then I bench press the tranny up into position (that bastard can get heavy), then once I slide a bolt through the cross member I put the jack under it, get the crossmember all bolted up, install the driveshaft and stuff then I fill the tranny through the shifter hole and then install the shifter.
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