Okay, with the C-clips in, pull the axles straight out until the C-clip is sitting flush with the spider gears, kinda like the one on the right in this picture. Don't worry, you'll know when you've got it all the way in; the pinion shaft won't go in unless the C-clips and axle shafts are fully seated.
Attachment 31233
Install the pinion shaft. The book will say you're supposed to replace the pinion shaft retaining bolt...the only time I replace them is if I stripped one out on removal or I'm replacing the ring and pinion since a new gearset comes with a new pin anyways. Clean the pin threads with brake cleaner, and clean the threads in the carrier with brake cleaner. Put a dab of blue loctite on the pin threads (not red or green!) and torque it to 22 ft/lbs.
Attachment 31234
It's all downhill from here. Take the differential cover and clean it up. If you've got access to an air compressor and a die grinder, that's the easiest and fastest way, but a razor blade and/or a wire brush will work too. It doesn't have to be clean enough to eat off, just make sure you get any big blobs of sealer off the surface of the cover where it meets the axle housing.
Attachment 31235
I've seen some folks get real carried away with RTV sealer. A little goes a long way here, guys. I install the cover immediately upon applying the sealer. Torque the cover bolts to 24 ft/lbs.

Here's the cover installed. Don't forget to put your axle ID tags back on a couple of the cover bolts.
Attachment 31236
Now we've gotta fill the axle back up. First, remove the fill plug. It'll be on the driver's side of the axle housing, and it's a 3/8" square drive. Get a pretty long pull handle if you can, sealer was applied to the plug from the factory and sometimes they can be a bear to get out.
Attachment 31237
It'll take just a bit over three quarts of fluid. Fill it 'till the fluid is just at the bottom of the fill hole. If you've got a limited slip axle, there's an easier way to add the friction modifier than through the fill hole...
Attachment 31238
I remove the ABS sensor (it's held in with one 10mm bolt) and use a small funnel to dump the modifier in. Be advised - friction modifier smells like death. Seriously. Don't get a drop of that crap on you. It doesn't come out easily.

And finally, last thing to check especially with an axle seal leak is to be sure that the axle vent tube is not restricted. A blockage in the vent tube will allow pressure to build up in the axle housing, blowing seals out.
Attachment 31239


I hope this helps someone. From start to finish on this job, including time to take pictures, goof off with my co-workers and running back and forth between parts was about three hours. On a scale of 1-10, this one's about a five in regards to difficulty, or a 4 if you're replacing just the axle seals and not the bearings. Definitely something you can do in your driveway with a few basic hand tools.

Next how to...um, rear brakes and/or disassembly and lubing of the driveshaft slip yoke, depending on which one I get to first.

You're darn right. Makes me cringe thinking about.

Nice thread and writeup, Quintin. It's good to have mechanics like you around to show us the right way. :D

good how too thread, nice pics:thumbsup:

Great writeup Quintin! You made it look easy enough for any of us to do it. Now maybe a quick tranny teardown article? :D :lol: j/k

For those asking how much...

I had mine done at a local shop. They're not the cheapest in the area, but the ones I trust the most.

These are the prices they quoted me:
$175: Replace one seal
$275: Replace both seals
$430: Replace both seals and bearings

great write up

How many miles before someone has to replace the seals and the bearings?

I had 54K miles on mine before an axle seal started leaking.

I've got over 170K miles on my dad's '97 F250 LD and I've never gone into the axle in it. Figure that one out.

Quintin, excellent write up. I'm sure this will help someone. :thumbsup:

Good job Quintin.:thumbsup: Now people will understand why a job like this costs so much.

Mine were leaking on one side after 39000 miles.
I had both seals replaced.

Excellent writeup.......:thumbsup: looking forward to the next ones