be sure to have front wheels securely blocked!
Difficulty: 4 out of 10
I guess it depends on your skill set, no need for fancy difficult stuff like you would need for a differential setup, if you can do your own brake work and fluid changes, chances are this will be pretty easy for you to deal with.
Time to install:
id say no more than a couple of hours.
block front tires, remove both rear tires & brake drums, remove diff cover, remove cross pin, remove axle "C" clips, remove axles, pull old seals, clean everything, install new seals, reinstall axle shafts & retaining "C" clips, install cross pin, install rear cover, refill with oil.
-blocks for front tires, i used 2x4 scraps
-small floor jack
-tire changing tools
-3/8 drive ratchet/sockets (probably metric sockets)
-1/2 drive torque wrench with 3/8 socket adapter
-5/16 wrench with 6 point box end
-small hammer, i used a dead-blow with a brass head on one end, plastic dead-blow head on other end
-2 cans of brake clean
-2 lids from a gallon ice cream pail (you'll see why later)
-small pocket telescoping magnet or needle nose pliers
-small amount of light grease
-red grade Loctite
-a few clean rags, maybe more than a few.
-seal puller (sears has a basic one for 10-12 bucks)
-gasket scraper or good putty knife
-2 axle shaft seals, about 4 bucks each at my local Auto Zone
-80w/90 gear lube, if you have a limited slip, be sure to get the oil or additive for that
-2 cans of brake clean if you don't already keep some on hand
-some loctite i went with red i already had, blue would probably be o.k.
-either rtv or gasket for rear cover
Have you noticed a oil leak when doing a brake job? Don't let it ruin the shoes and affect braking ability, the risk of running the differential low on oil, and the mess you'll have the longer you let this problem go. I started with blocking the front tires, there will be times to have the transmission in neutral and time you will want it in park or 1st (depending on trans type) after blocking the tires, slide a pan under the rear differential and remove cover bolts, crack the cover loose so the oil starts draining out. while its draining, take off both back tires, place jack stands under the axle housing at each side and remove brake drums. place floor jack and blocks under rear bumper (receiver hitch if you have one) jack up body about 2-3 inches to give yourself some working room, but not so much that your off the jack
stands. remove rear cover completely. you will now want the transmission in neutral. rotate the ring gear until you can see the retaining bolt for the cross pin.
when it is directly in the middle, cross pin level, go put the trans in park or 1st gear to hold the drive shaft-ring/pinion in place. the cross pin retaining bolt is a 5/16 hex head, it is in tight and with loctite from the factory, get a 5/16 wrench with a 6-point box end and put on the bolt, tap with a hammer to break it free.
once you remove the retaining pin, go put the transmission back in neutral so the carrier will move, turn the carrier and the cross pin should slide out.
once the cross pin is out, push each axle shaft in one at a time and remove the "C" clip retainers.
i used a magnet, needle nose pliers will work also. once the "C" retainer clips are out, the axle shafts can be removed.
before you pull the axle shafts out, put a shallow tray, like the top off a gallon ice cream tub under each brake assembly this will catch any oil that is still in the axle tube, and when you spray brake clean later it will catch that nasty mess. remove axles and slide them into the back of the bed. the driver side shaft is longer than the passenger side by about 2".
(I didn't measure, but its a noticeable difference) remove the old seals, sure you may only have one leaking, but do both, you're here anyways, its only $4.00 per seal and you shouldn't have to do this again any time soon. I use a seal puller from sears,its kind of like a pry bar with curved sharpened ends, its about 10-12 bucks, a lot easier than trying to use a screwdriver.
once the seals are out, stuff a small rag into each bearing and spray the heck out of your brake assemblies with brake clean.
since you're doing this job probably because you have a bad seal, this is the time to get all the nasty mix of hypoid oil and brake dust removed.
mine was leaking just bad enough to run down the inside of the back plate, wasn't soaking the brake shoes yet. if yours has gotten that bad you may want to put new brakes on.
also clean the axles at the wheel flange end, use a little Scotch brite where the seal/bearing rides.
next compare your seals, I was given the wrong ones and had to go back, even though I gave the correct information, it happens, this is one of those times you're not sure you have the correct part until its time to re-assemble.
when your sure of your seals, gently tap into the bore. I don't have a socket big enough to use as a driver, I've used a small 2x4 block before, but I've done enough seals that I just usually tap back and forth then work my way around the seal until its flush with the housing. this is no place to rush.
once the seal is in, take some light grease and coat the inside lips of the seal.
I also coat the axle shaft where the bearing/seal area is. next slide the axle shafts back in.
there is a small o-ring there where the retaining clip goes, not sure why ford does this, g.m. uses a similar retention design but no o-ring.
push the axle shaft all the way in, slide a clip onto the axle are where it goes, then move the axle shaft back out to seat the clip within the side gears. spray the threads of the cross pin retaining bolt and the threads where it goes in the carrier with brake clean. you may have to move the carrier slightly to line up the carrier with the spider gears, and sometimes the spiders like to move a little when your moving the carrier without the cross pin in place.
once the cross pin is in, slide the retaining bolt in, but don't tighten. put some loctite on the threads before tightening. this is one bolt you do not want coming out! place transmission in park or 1st to hold carrier in place so you can tighten the retaining pin down.
clean up your cover and the mounting face of all silicone or gasket material. wipe down with brake clean. from the factory a lot of these used no cover gasket but just rtv silicone. you can get a gasket if you choose. I have a aftermarket cover and prefer a gasket. after you clean both surfaces, take a break and slide the brake drums back on.
adjust brake shoes if needed (my self adjusters don't work, I'm sure many others have this issue) use whatever method you wish to seal your cover, rtv or gasket. put cover on and start all the bolts.
the torque for the cover bolts I'm uncertain of, Haynes book didn't list it, I went online and found various figures anywhere from 15/20 ft pounds to 25/35 ft pounds. i would think the lower figure is for the composite cover, the higher for a steel cover. I went with 25 ft pounds myself. remember to tighten it down like you would a tire or cylinder head, go back and forth across the cover to torque it down evenly. next fill the differential with oil, remove the plug and put oil in until its running out. will vary with axle type and mine takes more than it used to because of my cover.
I used a gallon jug of 80w 90 std gear oil from Wal-mart. the pump made this very easy to deal with. took a little over half.
it was a little easier with mine due to the design of my rear cover having a rear drain and fill hole. be sure to use limited-slip rated oil if you have a limited slip.
last, put your rear tires back on and tighten accordingly. be sure your in park/first before removing the jack and blocking. with the right parts and tools on hand this isn't too bad a job to tackle.