We did it on a tree outside of our home and occasionally I've had success with it in my small (but very cool) greenhouse with some of those plants though I've never tried it on a Jade. Try wrapping gauze around the wound as you would your own, it may heal itself. I don't know that I would seal it though with tape, the moisture may make the trunk rot.

actually, your jade may be nearing the "end" of it's life. if so, just cut it above the split and root the top. that will stimulate growth where you cut it on the bottom too. sometimes, they just get too big for their bases! just let the cut dry out well before you put the stem in the soil in the same pot, and water as if you hadn't done a thing to it. they are very resilient plants ans some of the easiest to propogate.