Yo C,
I think it has been done with much work detailed, but the Web sites with the information are long gone.
Here is what I have found over the years;
ZF S5-42 (5 speed):
"...Since it was 3 days of not having to go to work I figured it was a good time to swap in the ZF tranny I had taken out of the donor truck, last november.
Like all the posts about the swap had said, it was straight foward. It was nice not to be held up by having to make runs to the part store.
Other than the stupid shade-tree (me) dropping the cups off one u-joint and losing the bearings.
I like the gear ratios on the ZF. No more slipping the clutch to reverse up a hill, and I can start off in second.
The trade off is more gear whine coming from the transmission....
I am currently trying to make the M5od fit where a T18 was so I now understand some of those questions. I just thought going to the ZF was so easy.
The clutch setup is the same for both the m5od and the ZF. They are both internal clutch slaves with the same connector. The 4 speed is different with the external ***** and pressure plate.
The shifter for the 1356 worked just fine on the ZF setup. The t-case shifter on the T-18 had to be swaped when I stuck the m5od in. (differnt length linkage)
I had to laugh when I pulled out the t-case and m5od. I was expecting weight. When i could bench press the complete tranny and t-case, I just figured, "this is gonna be so easy." Then I went to stab the ZF in! That is what a tranny is supposed to weight..."
...
ZF 5 speed swap pic's in a 78 by 78bronco460
http://www.supermotors.net/registry/605/65531-4
http://www.supermotors.net/getfile/853535/fullsize/p8020257.jpg
"In that picture the trans is in 1st gear, and it's not a bad reach. I've been trying different lengths and bends, mostly because of the throw, but I have three other shift sticks (for the t-cases) to consider."
Good luck!