93 mercury villager

If you are speaking about the rear drive axle and there are no flange nuts (4) behind the axle flange (where the lug studs protrude) then you will have to take off the rear differential housing cover. Otherwise you would remove the 4 nuts and use a slide hammer to pull the axle. If there are no nuts behind the axle flange then do this. You should have both the rear wheels off the ground. Make sure you have car level and wheels chocked good as the car will roll. Remove the housing cover usually (10) bolts.Catch the gear oil in a pan (will take a while to run out when cold) there is a large steel pin going through the large rear gear about the diameter of a nickel and about 6 inches long. The transmission should be in neutral in order to rotate the rear gear. On one end of the gear pin there will be a locking bolt going through the large gear pin. Rotate the rear around by turning the driveshaft until you find the lock pin bolt. The 5/16 bolt head is small and you will need a good wrench prefer. a 5 hex point and the longer the better to get this long thin bolt loose. aim the gear pin down towards the bottom portion of the opening of the differential opening by rotating the driveshaft. This will allow you to see through the hole in the rear and see the "C" lock. Remove the pin and slide the pin down and out but do not rotate the rear after the pin is removed. Both axles are held in with a "C" lock type washer. Push in the axle from the wheel side it will go in about an inch and the C lock will fall out. Then pull the axle straight out without rotating the axle. Put in the new axle without rotating it just move it enough to find the spider gear splines. Push it in all the way. Put the C lock back in the axle groove and push the axle along with the C lock with your finger tip outwards towards the wheel until the axle and C lock slide flush into the spider gear. Insert the pin (you might have to rotate rear slightly to get pin through if you moved the axle too much while installing it ) Put the long locking bolt back through the pin hole and tighten. You can use silicone or a new housing gasket make sure surfaces are clean then remove fill plug and refill with gear oil. Usually hold about 2 quarts. Sounds tough but it really isn't that bad.