Uhm, first, not to be rude or anything, but typing in all caps is considered yelling and is difficult to read.
Second, I highly doubt that the mustang driveshaft will fit in your mountaineer after you do the swap. I am assuming that you will be deleting the transfercase as well... Get a driveshaft from a 2 wheel drive mountaineer (of course this may not work due to the front flange, you might need a custom made shaft)
If you want to permanently tranform your truck into a 2 wheel drive truck, you will need the 2 wheel drive steering knuckles,
Then to remove your front differential:
Pop off the "hubcaps" and loosen the axle nut a little.
Jack up the front of truck, get it on jackstands, preferably held up on the stands by the frame
Take tires off, remove axle nuts ..have someone hold the brakes if needed, remove brake caliper mounting bolts, remove caliper, hang it by a wire and do not let it hang!
Remove rotor, loosen the pinch bolt on upper balljoint, drive pinch bolt out with a drift if needed, remove the cotter pins from the castle nuts on the lower balljoint and tierod end, loosen both castle nuts but only remove the castlenut on the tierod, strike tierod with rubber mallet to remove it from knuckle, on the lower balljoint (castlenut still in place but loosened to the point of almost coming off) strike the steering knuckle on the round part of the steering knuckle where the lower balljoint passes thru. don't be afraid to hit that sucker hard - you won't break it - the knuckle shouild drop down to the castlenut, lift knuckle off castlenut and remove castlenut, remove knuckle from CVaxle.
Climb under truck, insert long screwdriver (or tire iron) between the inner flange on the CV and the front differential and pry out the CVaxle, Remove CVaxle. Your done on one side, do the same for the other side.
Now, climb under truck, remove what front diff cover bolts you can, insert screwdriver between the cover and the diff to drain out the fluid, climb back under the truck, look at the drivers side and you will see an "A" bracket that connects to the frame from the differential, remove the bolts on the truck side of the bracket - leave the bolts in on the differential side, go to passenger side, repeat process. The diff will just about drop out.
Before putting it all back together, this time using your two-wheel drive knuckles, now is the time to check all your front components (Balljoints, tierods) replace them as needed.
