The axle seal on the driver's side started leaking many miles ago. The biggest headache it gave me was that every time I drove through a creek or through water I had to change my gear oil because it would become contaminated.
The front axle is poorly designed, most notably because of the lack of a dust boot or seal on the outside of the axle tubes. There are 3 axle shafts in the front end, the driver's side shaft, the intermediate shaft, and the passenger's side shaft. The axle uses a vacuum operated shift motor to lock the shafts together, since the hubs are a one piece design and cannot be unlocked. There is no gear oil in the drivers side axle tube. The seal is on the differential carrier itself, requiring the differential to be removed in order to change the seal. The other seal is on the outer side of the CAD housing. Everything between these points is covered in gear lube. Everything outside of the seals is open to the elements, meaning every time you go through the mud, you pack the tubes with grit. Traveling down the beach really accumulated sand in the tubes. This causes the seals to become contaminated, causing them to leak over time. I've also had alignment techs put the axle in wrong, putting the seal in a bind and causing a leak.
Good seal on right, bad on left. Note how the bevel is missing on the bad seal!
I recently developed a squeak on the drivers side. At first I thought that the wear indicators on the breaks were the cause, but the brakes had plenty of pad on them. The squeaking became more pronounced during a turn, and then quieted down once the steering was straight. I inspected the ball joints, and ruled them out. Then only thing left was the crossjoints connecting the inner axles to the outboard stub axles and hubs. WD-40 applied to the joints temporarily quieted the noise, but it soon returned. I had narrowed it down enough to make the decision to change the crossjoints and axle seals in one fun-filled day of front axle bliss.
This procedure applies to Dana 60 front axles found on Dodge 3/4 ton HD and 1 ton pickups. The design of the front hubs and rotors changed for the 2000 year model, but from 1994 to 1999 the axle was relatively unchanged. The same procedures should apply to a Dana 44 found in 1/2 ton trucks, but there's no guarantee.
FRONT AXLE SEAL - DRIVER'S SIDE
Start by jacking up and supporting the truck with jackstands. Using a 7/8 socket, take the wheels off. Use a 3/8 hex socket to remove the brake calipers and hang them on the upper track arm. Be careful not to break the rubber brake line holding the caliper to the frame. Now for the fun part.
Behind the rotor, there are 4 12 point bolts that hold it on the steering knuckle. Use a 12 point socket so you don't have to go crying back to the dealer to get new ones when you strip out the heads using a 6 point socket. A 5 inch extension and 1/2 drive ratchet work perfect in this case to get the bolts out. Don't worry about the rotor assembly sliding off and smashing your toes, it won't.
We'll do the driver's side first. There will be 2 brake dust shields behind the rotor that will come loose with the whole assembly. Put the rotor and dust shields to the side and slide out the axleshaft. If you don't plan on replacing the axle seals at this time, be careful to pull the axle out of the axle tube straight to prevent the splines from getting contaminated with dirt and sand. This step is more important when you go to put the axle back into the differential.
Take the diff cover off. Unbolt the differential carrier caps and remember the orientation of the caps and bolts. These have to go back in the exact way that they came out. Drop the differential carrier out of the axle. A small prybar is necessary to do this. You will also have to take the tie rod lose from he steering knuckle on the drivers side in order to clear the differential when it drops out.
Jump to the next section for instructions on cleaning out the axle tubes.
The seal is on the outside of the differential towards the drivers side. Install the drivers side seal in the differential using a bushing driver. If you're like me you can use a 1 3/4 socket, but don't bend the seal. I put a small bead of silicone on the outside of the seal, just to ensure that it doesn't leak. This is the easy seal. Pat yourself on the back, drink a beer, and lets celebrate some South Texas ingenuity. Fill everything up, install the axle, and the drivers side seal replacement is through.
FRONT AXLE SEAL - PASSENGER'S SIDE
The passengers side comes off the exact same way. If you're going all the way to the seals, go ahead and pull the axle all the way out. The CAD shift actuator is held onto the axle housing with 4 7/16 bolts. Just unbolt them and hang the motor out of the way next to your brake caliper. There is a cork gasket between the motor and axle housing, be sure to scrape it off and seal it with RTV when it goes back together. The shift collar can be removed and cleaned up. Slide the intermediate axleshaft out, using your fingers through the CAD housing. Pull the shaft all the way out of the axle housing.
Now, using a long punch drive the seals out from the outside of the axle housing inwards. I used a 4 foot piece of 5/8 all thread. This is probably the handiest tools to have for this project, trust me. After the seals are out, now you can go about cleaning out the dirty axle tubes.
For cleaning the axle tubes, you need a blow gun and compressed air. While the air is blowing, take your handy piece of all thread and ram it in and out of the bottom of the axle tube, dislodging all of that dirt and sand. Be sure to wear eye protection, this stuff gets blasted out of there. Continue until all of the accumulated mud has been dislodged. Take a can of brake cleaner and soak the tube inside. Use the blow gun to blow the brake cleaner out. you can spray the brake cleaner behind the blowgun, creating a high pressure parts washer. Finally, take a rag and force it throughout the axle tubes with your handy piece of all thread from the outside in towards the differential. Spray with brake cleaner and swab. Stuff the tubes with rags to avoid further contamination. Repeat this process for the other side. There is a roller needle bearing on the inner side of the CAD housing. Blow from the CAD housing out through both sides of the axletubes. You don't have to clean the tube between the CAD housing and the differential, it wont be that dirty since there is gear lube in the tubes. About 4 cans of brake cleaner should do it. Don't forget to clean out the differential housing as well. These methods will insure that the tubes are clean and your new seals won't be contaminated when you reinstall your axle shafts.
The seal is on the outer part of the CAD housing. This gives you all of about 2 1/2 inches to swing a hammer. Put silicone on the seal and set it into place. Put your 1 3/4 socket into the housing and line it up with the seal as if to drive it in like the last one. Pass your trusty allthread through the driver's side axle tube, through the seal, through the socket,and into the differential housing. Be careful not to tear up the seal with the rough edge of the allthread. Thread a nut onto the end of the allthread and pull it back to the socket. There you have it, a home grown reverse bushing driver. Have someone else line up the socket with the seal and bang away from the outside. It is important to have a socket that fits the seal exactly, or else you'll tear it up. Bang the seal in and pass the allthread back into the diff housing and remove the nut and pull it out. Tell all of your friends that you thought of this yourself and bask in the glory.
CROSSJOINTS AND WHEEL BEARINGS
There, the seals are installed. Now for the crossjoints. These install just like a standard u-joint, but they are larger than most people have ever worked with. No problem, just go through the same procedures with a vice, hammer and screwdriver to seat the c-clips. Remember to install the grease zerk fittings into the joint before installing it back into the truck.
Here's how to replace your bearing housing. Remove the cotter pin from the axleshaft and discard. The retaining nut is 1 11/16, so be sure you have access to a large socket set. I had to use a 3/4 drive Ingersol impact wrench to break the nut loose. Remove the nut and washer.
The bearing housing is pressed onto the outter stub axle shaft splines. It may take some hammer blows to free it. If it is really tight, you may have to put it in a press.
Once you have separated the bearing assembly from the axle, install the new one. I use neverseeze on everything, splines, bolts, etc.
Install the axle back in the axle and bolt it up to the backing plate. Put the nut on the splines and tighten it with a reasonable ammount of preload. Install the cotter pin back through the castle nut.