[Alien5044]

I'd clean the area with brake kleen, let it dry thoroughly, then smear a liberal amount of JB weld on the part and the case and press it back together. Just don't let it blob into the case. Let it cure good.

I don't think you will want to rely upon that threaded part to hold much force. It looks like one of three attachment points and if those are under much stress, the JB Weld may not have enough grip to stand up to it. That could lead to the other two failing the same way.

I do not believe that the trans case contains pressurized oil, it being mostly a reservoir of oil, so the JB Weld will likely plug the hole OK.

Others may have different or additional thoughts.

 

[Alien5044]

So if the aluminum trans bolt holes are not bearing the support of the plate, what does support it?

Unless I don't understand it, from the pic it looks like there are 3 bolt holes in the trans that hold the support plate. My guess would be that the one that busted out, may have come a little loose, allowing the plate to slightly flex right and left, with the two other bolts acting like an hinge point, and letting the movement hammer that loose bolt until it broke out the casting. The bolts on the left have mutual support whereas the one on the right has no other support and likely subject to any flexing pressures exerted by the use of the implement.

Sort of wondering if you could fabricate a steel cross beam between the frame rails to support the bottom of the plate rather than through bolting to the trans casting. ??