So while my truck was on the lift in the shop this morning having the steering pump replaced, I decided to test the ESOF system to make sure it's ready for winter. Everything works normally, both hubs engage and disengage in auto mode without a problem. The problem is, if the steering angle is anything other then straight, the passenger side axles gets locked up. This is not a problem in 2wd because the ESOF unlocks the hub, but in 4wd you can't make even a slight turn. Do I need to just grease up the bearing inside the hub using the guide in the tech folder or is my hub shot? The u-joint looks fine but I haven't ruled that out either.

Also, the dust covers on both hubs seem to have come loose, the inner seal is still there obviously or else the ESOF wouldn't be able to lock the hub. Could this be the problem? Loose seal let some dirt in and that jammed the bearings up?

 

Those seals were poorly designed. They are hanging on almost every super-duty you will find. There is no bearing behind them, as they are only protecting against mass intrusion of mud/dirt into the axle tube itself. Water gets past them easily.

Did the passenger side axle lock up on the lift or on the ground? Your tire/wheel is riding on that hub bearing all the time regardless of whether the truck is in 4x4 or not. If the bearing is bad, you will hear noise from it or the truck will pull while driving down the road. With the tire off the ground, spin the wheel. It should spin without any growling or other noises. A brand new bearing will only make one revolution or less when free spinning the wheel like this (tight). You can also grab the tire and try to move it back and forth with hands at 9 and 3 o'clock. While pushing pulling with hands at these positions, you are feeling for excessive play and any subtle clunking/clicking from the bearing. Also try this with hands at 12 and 6 o'clock, keeping in mind that ball joints also feel similar when they are worn out.

 

I don't have first hand experience on this subject, I replaced everything at 154k on my previous EX... Replaced my hubs on current Ex shortly after I bought it... ESOF working as it should, so not touching. I do engage 4x4 every month, and at beginning of this year I got to use 4x4 for 4 days in the snow and a few months ago 2 days in the sand
I've always heard negative remarks on OEM, but have never had a problem with mine.

 

The dust ring on the axle tube is indeed hanging on both sides, but I'm not too worried about that one (even though I probably should be). The one I'm referring to is on the backside of the hub on the wheel side (outer) of the u-joint.

It only locks up when the hubs are locked in 4x4 mode and you turn the wheel a little. I noticed it when I used 4x4 in the pouring rain we had the other day. It was slipping off the line in 2wd so I figured I'd give the 4x4 a workout. All was good unitl I tried turning, It would barley move. At first I thought it was just driveline binding but when it was on the lift today I checked it out. If the wheels are pointed straight and you give it a spin it goes around about 1 or 2 times just fine, doen't matter if the hubs are locked or not. But if you turn the wheel a little while the hub is still locked it doesn't budge. If you turn off the 4x4 and let the hubs unlock, it spins fine even when the wheels are turned (because now the axle is not spinning anymore). So it's either a bad u-joint (possible, but it looks fine) or something is wrong in the hub. It seems there are needle bearing in the hub where it mates to the outer axle shaft. I think that's where my issue is. Has anyone else had this issue and found the needle bearings to be the culprit?

See this link for more info on the needle bearings/outer axle shafts, I found it in the tech folder Welcome to guzzle's 4x4 Needle Bearing Maintenance Web Page

Thanks Stewart for putting that tech folder together, reps sent!!

 

It sounds like your u-joints are seized up. That is what most likely wrecked your pump. The u-joints must be free for the wheels to turn (left and right) even in 2 wheel drive. The hub and unit bearing have to be removed to get the shaft out to change the u-joint. This is a good time to inspect the ball joints and replace them if needed. If you have the money, just replace them while it's this far apart. There is a new style seal available that's easier to change and supposed to work better. It looked a lot better than the original design, but costs more. We have lock out hubs, so our old ones were good enough to reuse.

 

With the additional info, I agree with Lance. Likely culprit is your U-joint. I am not seeing at all how it could be the hub or the needle bearings in the hub.

 

Sounds like it's time to replace the U joints.
Good news is that you will have new seals at the same time!

Just did mine and it was a pain in the ****.

 

While my U-joint may be bad I would be reluctant to state that it's the cause of my pump failure. I recently had a Redhead box installed and the pump was perfectly fine before that. I would attribute it to corrosion (it was slow leaking from just behind the pulley) and possibly a rough handed mechanic....

I'm hopefully going to get that U-joint inspected/changed later in the week. I'll try to do new seals and grease the hub once it's all apart.

 

If you tear down to get to the U-joint, you will need to have new seals to put it back together. I have heard of some folks getting it apart and reusing the seals, but I would not if it were me (and it has been me before). Here is my adventure from a couple of years ago: https://www.ford-trucks.com/forums/1...haft-play.html

Some good part numbers in there I think.