Axle tube seals? Vibration from frontend in 4x4
 

Ok first off, what are this things the looks like seals that are in between the yoke and the axle tube? Do I need to replace them? They look like they are hanging out.

Second I have a terrible vibration from the frontend while in 4x4 this occurs most noticeably at full coast or light to hard accleration. Part throttle cruising not near as bad but, it is there.

I thought I had a wore out lockout on it so I replaced them, checked the fluid levels in the diff and transfer-case (they were full). So I am thinking dry u-joint maybe? The truck has 176,000miles on it, and the 4x4 has rarely been used.

Check the dual cv joint thing on the front driveline where it meets the transfer case. I had my whole front end rebuilt because in 4 wheel drive it sqeaked and clunked...thought it was the hub or ujoints. It ended up being that joint at the transfer case was gone and 100 percent dry(it is a ball in socket type joint betweent he u joints). Cost me a little over 400 bucks to get it rebuilt.

I have a different question for anyone who could answer: I own a 2004 f250 SD 6.0 Fx4.When I take off and at slower speeds(even when decelerating[<50mph]) i get a vibration from the driveline somewhere. could it be a ujoint or should i check the carrier bearing? I had a new detroit locker put in the rear end a year ago but that cant be it because it had the vibration before the new rear end.

In regards to the axle seal, the actual seal is on the inner pumpkin side of the axle tube, not the outer like the rear. Unless you are leaking, I'd leave it alone. The outer seal is just a dust seal and most are broken and hanging. You may have a bearing problem. The front axles use two bearings, one needle with the hubs unlocked, and one larger bearing for locked. The little bearing is replaceable with a timken bearing from napa, but since you mentioned a problem in 4x4, your hub assembly is probably shot.

In regards to the other poster on vibration, if you have a carrier bearing, it may have to much of an angle on it, causing a vibration or shudder on take off. You can add some shims in 1/4" increments or so to make the shudder go away. If my truck is loaded the shudder isn't there, but empty it is...

Hmmm, sounds like your vacuum seal is gone on both sides of the front axle. Check your needle bearings in the hub unit bearings. Park the truck, unlock the axles, push up and down on the u-joint. If it moves at all continue reading. If not, check all the ujoints.

Both of my needle bearings have gone out this past fall. Started a year ago on the drivers side with a tiny (possibly imagined) vibration. No one ever figured it out so I drove it till it made noise. Then drove it some more. 18,000 miles later and figured out what it was because someone else suggested the cause. While replacing the drivers side, double checked the passenger side to find that one was sloppy too. Just my luck.

Ford designed an enclosed unit bearing system with a small needle bearing insert on the inside of the hub that the axle stub rides on as it passes through the hub. No greasing is possible on that needle bearing due to the dust and vacuum seal. Usually it comes installed on the hub unit bearing but it can be bought separately.
Purchase a new stub shaft, needle bearing and seal. The seal will be a pain to get on the shaft but I've used a section of 4" exhaust tube capped with a 2x6 and then pounded it on. Only had one get ruined... (that's a good record right?)

You have to buy the new stub axle because the old one will be worn by the ruined needle bearing and because the shaft IS the race, there's no way to fill in the groove. I already checked that option at a machine shop.

It's about 200 in parts. Good luck. Now's the time to check your brake slide pins and grease those unit bearings through the ABS fitting hole.

I have a clinging noise coming from the front end of my truck as well. Its only noticable when it is coasting with very little pressure on the fuel pedal or completely coasting at about 60mph, but it doesnt do it as bad with the hubs locked in. I can tell there is a lite vibe at about 55-65 under acceleration too. Ive checked the driveline u-joints myself but couldnt feel or see anything wrong and my truck only has 23000 on it!!!!!

So you are talking about the bearing that the stub axle rides on inside the spindle. There are two bearings in there?

I just replaced drivers side wheel bearing over the summer and passenger side the summer before.

If the u-joints are original with 176k miles, I'd replace them and see if it fixes it. That seems a likely source as it is only in 4x4 mode (and a good idea anyways). Otherwise the wheel bearings, I'd say.

Others may have more informed opinions, but there aren't a lot of components to the front drivetrain.

Art (Krewat) at one point had been posting a copy/pasted blurb about turning the ujoint by hand in 2x mode. It should move and not seem rough. If it is rough, then the needle bearing was the issue (I think). You can search for that to be sure.


-Dave

Yeah, there is a smaller needle bearing assembly that with unlocked hubs, allows the hub assembly to rotate around the stationary stub axle. When the hubs are locked in, the hub assembly rotates in unison with the stub axle. A larger bearing is used when the hub assembly is locked in as the hub needs some bearing to rotate around and allow the 4 studs holding it to the knuckle to stay stationary. In other words, the stub axle receives power from the transfer case in 4wd hi and low, and in order to drive the front wheels, the hubs provide the mechanical lock between the wheels and the stub shaft. Unlocked, the stub shaft doesn't rotate, but the wheel assembly does, so the needle bearing you can see is being used. When the hubs are locked, a larger bearing is used (non servicable to my knowledge) as the stub shaft and the wheel assembly have the same angular velocity. Since the needle bearing is rotating at the same velocity as the stub shaft, the larger bearing is then used to allow the powered wheel to spin in relation to the otherwise non rotating 4 stud knuckle assembly...

The hub assemblies up to the 2005 redesign are slightly rebuildable if that makes sense. If you find your needle bearing is bad (it is the only visible bearing), you can actually replace it with a napa needle bearing, saving yourself big bucks. Additionally, the only hub assemblies I would recommend are Ford ones; the others don't seem to hold up. Let me find the part number for the needle part.

Just for reference, if it turns out to be the needle bearing, it is a torrington hb20 bearing, but torrington got taken over by timken so it is a torrington number, but timken bearing. Costs $12.00 from napa. Just drive the old needle bearing out, and drive the new one in. Make sure you grease it.

Thanks much, will be tearing into it this weekend.

Ok, this is what I found. I got the chance to change out the passenger side lockout, and it was locked up even in auto. The drivers side was like this over the summer and I took it apart and cleaned it. Truck now has a set of Warn locking hubs on both sides.

The u-joints in the driveshaft are fine.

Now for the part I forgot. Over the summer I would get this terrible driveline vibration, that upon engaging the 4x4 would stop. So I just locked the hubs in and it stopped doing it.

Now that manual hubs are on, in 2wd with hubs unlocked I get that vibration again. It won't stop until you stop the truck, but doesn't stay in sync with vehicle speed. When you slow down it continues the same vibration then slows down, like something is spinning freely.

THAT'S THE SAME VIBE I GOT!

If you find out what the vibe is...... GOD could you please post up the fix?

I have rebuilt the rear half of the rear driveshaft, replaced the carrier bearing, replaced all the back u-joints, greased the entire back axle, changed out the rear diff fluid, replaced all the needle bearings in the front, replaced both knuckle seals and front axle seals. Rebuilding the front drive shaft and doing the lower ball joints tomorrow. The front axle u-joints are great... so no need to replace those yet.

I think I'm going crazy.:-X24

Have someone watch and observe if the front drive/axle shaft shaft is spinning in 2wd mode. Sounds like one of the bearings in the front ub or the axel is not disengaging properly...