My front autolock hubs on the 2004 350 are suspect. My master tech friend tore into them to fix vacuum leaks that were making the pump work overtime. He warned me that they are on their way out. So I turn them to lock when I need 4wd. Today we were hauling gravel in 4L on trails, and at one point used a few feet of pavement to turn around, towing an empty dump trailer.

On the asphalt I heard a clickety clickety bad noise from the LF hub, so I unlocked it. Totally forgot that vacuum will still keep it engaged. Back on the dirt, up a steep hill, clearly 4wd was still working.

But later while jockeying the loaded trailer (4 ton skid steer on there) in reverse up a slight gravel hill to park it overnight, it seemed like I only had 2wd.

All this gives me a couple questions:

1) Is this the failure mode for Ford autolocking hubs? They fail in reverse first?
2) Is it worth replacing these with the same type, autolocking? Or is a simple locking hub stronger? I see Mile Marker has them for $135.

 

They operate from a vacuum pump. That pump also operates your hvac system. If you hvac system is sluggish when you change settings then there probably is a vacuum leak and it is probably in the front hubs. Those hubs have a diaphragm in them that will pull the locking mechanism into gear when vacuum is applied. There could be numerous things causing them not to engage. Most of the time it is the inner seal at the knuckle that the axle rotates on. It is a large rubber O ring and it does wear out and deteriorate over time. On the flip side if the vacuum lines from the pump going to both axles or hvac have a leak you will still have the same issues.

The large O ring is a little bit of a pain to replace as the whole front hub and axle assemblies have to be removed to repair them.

If you can come up with a hand vacuum pump (My'ty) you can check for leaks of the hubs at the nipple where the vacuum lines connect at the knuckles. If they leak down then you are in for a new seal. If those seem OK then put the vacuum pump or tester on the hvac side and check it for leaks. That's about the only way you can do a proper diagnosis.

Edit to add: You asked why they go bad. It's a '04 model, it is roughly 16 years old and the parts are rubber. They are going to dry out and crack and leak.

 

To add to post above. If your hubs are working manually you could just disconnect and plug the vacuum line going to them from the pump and engage the hubs when you need them manually. Not the best scenario but will work if you aren't interested in spending money on new front seals.

 

They are apparently failing despite locked in manual mode but so far only when I back up. The vacuum stuff, I know. I'm wondering about

1) Is this the mechanical (not vacuum) failure mode for Ford autolocking hubs? They fail in reverse first?
2) Is it worth replacing these with the same type, autolocking? Or is a simple locking hub stronger? I see Mile Marker has them for $135.

 

Then I misunderstood your post. I thought you unlocked them but vacuum kept them engaged until you backed up. If you do the seals the factory hubs would be just fine. I haven't heard that they would fail in reverse first. That being said if they are being engaged while in motion then the locking dogs would start to wear on the corners and reverse failure could be the reason. They are like a crash box when being engaged. They will grind just like a unsynchronized transmission. If you are old enough to remember the old 3 speed on the tree transmissions early ones weren't synced and would grind if you tried to put it in gear without waiting on clutch to stop spinning. Same principal here.

 

Yep I sure do remember that. Did HS auto shop in the early 70s, Cottage Grove Oregon. The teacher even had a Chevy 3/4 ton with a 4spd stick where 1st was an unsynchronized granny gear. And I have observed that worn tranny gears often show up by popping out of gear on the overrun, as in engine braking. I've had a couple old vehicles that you had to hold in certain gears, going downhill. Others where any use of reverse meant holding it in gear and steering with the other hand.
This truck has 230k on it and came from North Dakota. The PO told me that he often faced snow drifts to get to work. So those hubs got used.

So, can anyone weigh in on the issue of which are the best aftermarket hubs? Mile Marker hubs are inexpensive, but...I recall that they were a family company that once made great hydraulic winches. Then then there was a nasty divorce or some dam thing like that and now they're just another Chinese-sourced company. I guess I could rely on Amazon reviews. 11% of the votes are only 1 star, and many comments are scathing about low quality and inability to fit at all.

 

Well I surfed Bezosazon for a while and checked out the negative comments on the non-OEM replacements. Lots of issues. Nobody secretly pays folks to leave negative reviews, I suspect. So I'm still on the fence. Warn hubs cost a lot, and we have a fleet of trucks in the family. Have to keep the budget in mind....

 

I see you said you have a lot of trucks in the family and I see that according to your sig. Are the auto hubs working fine on your other trucks of the same vintage? If they are then I would swap the hubs with one of those trucks for a day or two and see if the problem is still there or moves over to the other truck. Easy to know that way if it is the hubs or if it elimnate's them. The hubs are only held in by a snap ring. A needle nose pliers and two minutes of time and you can have them swapped.

 

I don't have ESOF, but as far as the Milemarker hubs are concerned I have had very good service from them versus the Warn hubs, I broke 2 sets of Warns and have over 300K on the Milemarkers, I do R&R them every 2 years and lube, a very easy job.

 

The 2018 is a Dana 80 so probably won't swap. The 1997 has manual Ford hubs. The other trucks are 2wd. So swapping isn't an option, alas. But the vacuum circuit seems to be working fine. I suspect that mechanical failure is my issue.

Quite a few reviewers echo your experience, but 11% disagree. I didn't look at comments on the Warn hubs before now. Only 3% are negative, and most concern receiving the wrong part. So the Warn hubs are doing better at 3% negative vs 11% for Mile Marker.

 

Ahh gotcha. I was reading in your sig and saw the '00 ex 4x4 listed so was thinking that one.

Edit: Now I see that as listed as gone. Sorry about that. Your sig is a bit confusing.

 

Been out hauling more road base on our private dirt road. I keep the hubs in Lock position all the time when I might want 4wd, even on the highway if it's just a short trip to town.

The LF hub keeps making an ominous creaking noise on sharp turns in 4L on dirt. But we know 4wd is still working uphill. Every time we load up, there's a steep bank to climb up out of the tank area. Backing up, not sure if I have 4wd, as mentioned in a previous post.

But I do know that I don't want any more automatic hubs. I like to have 2L as an option for low-speed ops like backing up under a gooseneck, or jockeying a trailer around on pavement. I think I'll pass on the Mile Markers with their 11% negative ratings. I wish there were an alternative to Warn. My industry contacts say that Warn has mostly gone Chinese, and quality has gone down.

Anybody out here running hubs other than OEM, Mile Marker, or Warn?

 

I believe Yukon makes some, although I don't know if they do for your year.

 

The OEM hubs aren't that great, I had 2 sets fail within a year, I switched to Mile markers and haven't had any problems in 3 years.

 

I wish there were an alternative to Warn. My industry contacts say that Warn has mostly gone Chinese, and quality has gone down.There isn't anyone that has MADE IN USA parts anymore. It's called Global economy. You MAY find a company that has Assembled in the USA, but not made in USA. It's all gone over seas, Pay scales are way way cheaper in the Asian countries than here. The U.S. doesn't have the steel mills or the machine shops to make these parts any longer. It's all about profit margin and bottom line, so the best you can do is check the reviews on items and take your best shot. Manufacturing is coming back the this country, but it's going to be slow to do so, and even them, it's probably going to be using parts from overseas. Look at all your Fords, Chevy's, Dodges, the majority of parts are from out of country, Engines manufactured in Canada, transmissions made in Mexico, relays made in China, Taiwan, India, Nothing is hardly MADE here.