You can not use the Tacoma W59 tailhousing on the Supra W58,
there are different size bearings for the shafts.
I thought I'd share that to save ya the hassle..
Now we address the speedometer drive gear.
On my sourced Supra W58, the car used a speedometer driven cable.
There is a little metal tab holding the gear drive dealy in the transmission held in with a 12mm bolt,
in my case it was broken on the outside and I wasn't sure how to remove it.
A little research showed that it just pops out.. So I pryed it out of the tailhousing from the inside and it just popped out, its a snug fit.
Clean up your hole (give it a sniff while your in there) giggidy...
Wipe it off with a rag, now put in your Tacoma gear/sensor in it.
Now bolt in your Tacoma gear sensor with your 12mm wrench.
Don't forget to swap in your reverse switch (near the fill plug)
Now, as you scrape all of the old sealant crap off of where the tailhousing meets the sandwich plate,
before you reinstall the tailhousing, Use your Tacoma's shifter loop and slide the tailhousing down
a little bit so you can slide that onto the shaft before you drop the tailhousing all the way down.
Also, pop the shifter on there and run through the gears before tightening down the tailhousing bolts.
apply your new sealant, let it tack up for a few minutes then slide the tailhousing back on.
Now tighten your shifter loops 12mm bolt and your good to go!
Tighten your (9) 14mm tailhousing bolts, I don't have torque specs, I just wing it.. Don't get crazy, it's ALUMINUM!!!
This is about it.. I recommend using a fresh seal on the output for the driveshaft.
Reuse your Tacoma's shifter and top part of the shifter, bolt it in the same way you removed it, enjoy a longer 1st and 2nd gear with a slightly better highway gear.
Now swap your Tacoma W59's bellhousing on to the Supra W58, reinstall your clutch fork, throw out bearing, ect.
There are plenty of other How Too's on here done quite well..
I'm more of a visualist, so that's why this one exists.
Note: You "Mite" need shorter bolts when bolting your transmission mount back up to the 4 bolts on the tailhousing.
I brought my transmission to a guy for a once over..
I'll have it back on Thursday