The "drive" is the "PTO". Power Take Off. Six bolts will remove the rectangular cover, and by peeking under there you can see where it'll be prudent to have the transmission oil drained before you remove the cover...
The PTO it's self will bolt to the same bolt holes as the cover plate. Looking at the PTO you will see that some "holes" can not accept bolts, and require studs with nuts.
You can go to almost any truck or equipment dealer and get Spicer, Chelsea, or Munsie stud kits, (the short ones for a direct mount, I don't have part numbers handy). They'll have studs that are 3/8 coarse on one end to fit the transmission, and 3/8 fine on the other end to match the included nuts. Blue locktite, a stud collet if possible, otherwise great care... It makes the installation much easier and much more vibration resistant than coarse thread bolts.
You need some backlash in the gears. That's the PITA. You need to mount the PTO (two opposing bolts/studs torqued, and you need to actually check the gear that meshes with the transmission countershaft for clearance. .010 inches is ideal, which is just a tiny "bump" if you don't have a feeler gauge you can get in there. Heck, you can barely get in there at all via the PTO cover plate. Some folks have gone so far as to remove the transmission top cover to set it that way. You can "feel" an acceptable backlash between gears on the mainshaft and countershaft of the PTO it's self, that will be about the same backlash, and definately in the acceptable range. Better too loose than too tight, but the closer the better.
The gaskets are papery, dry, and it's hard to envision them working well to keep in transmission oil. Here's a tip. Keep the surfaces clean and trust the gaskets. The FASTEST way to make those little gaskets leak is to apply a sealer to them. The sealer seals the gaskets to the metal but isn't necessary, however the "gasket to gasket" joint where you stack the gaskets... Sealer makes leaks there.
All in all, it is not a hard job at all. It is a touch awkward at times, and if you don't get the shims (gaskets) right in the first time or two, the steps start to get VERY redundant, but it's absolutely not difficult.
One last thing... Watch the fuel lines under the injection pump. If somebody has installed, corrected, adjusted, replaced, or otherwise disturbed them while there was no driveshaft installed, there's a good chance that there'll be interference with the winch driveshaft. No big deal t adjust, no parts needed, but make sure you have the lines out of the way BEFORE you make your final bolted connection, as you'll need the driveshaft out for access.
