Ford Auto Hubs can cause spectacular failure

Hmmm.

2004 Explorer automiatic with 4WD, 97 Mazda B4000 5-speed 4WD.

Don't use the 4WD on the Explorer very often but the B4000 4WD gets a lot of work. Never had a problem with hubs except that now and then the Mazda goes "zzzzzzz" when the front hubs don't release -- drive about 10 feet in reverse and they release.

Still, I'll go out and do a few hard turns in both 4WD and 2WD at slow speed and at as high speed as I dare to see what happens.

OK, here's my feedback. You obviously don't understand how four-wheel-drive works.

Your transfer case (NOT crank-case) was in 4wheel drive on the interstate. That's what destroyed it. Just locking the hubs does not mean you are in four wheel drive, the hubs engaged and the T case in 2wheel drive means the front driveshaft is spinning, but just freewheeling. This is what happens to other makes (Jeep, GM, Dodge) which don't have front hublocks in their four wheel drive vehicles. If the hubs fail to unlock, it doesn't really cause all that much stress on the drivetrain.

I have had an F250 with the problems you described, but never had any catastophic failures. Granted, the vacuum operated autolock hubs are bad design, but the hubs alone wouldn't have cause your transfer case to explode. You must have been in four wheel drive on a high traction surface on a regular basis, which you should NEVER do.

What you are describing can only happen if you have the truck in 4WD High.

2003 and beyond 4WD Expeditions with those types of hubs leave the front hubs engaged when you are in A4WD (automatic 4WD). Either you stupidly left your truck in 4WD while driving on the highway, or something else is broken. Just locking in the front hubs alone will not cause the sort of problem you are describing. You still have a front differential, and if the drive shaft from the transfer case is free-wheeling, there will be no binding - just slightly reduced gas mileage and extra wear on the front axles. 1999 to 2002 4WD Expeditions didn't even have disconnects on the front driveshafts. The front axles were always engaged.

You need to either realize you left the truck in 4WD on the highway, or have the real problem diagnosed.

Ed

I thought this story sounded odd, and what you and Matt said makes perfect sense, and also explains why Ford wouldn't cover it!

Jeff DeWitt

Ed White wrote:

Yes those auto hubs were pretty unreliable on my 95 f150 4x4. i replaced with warn manuals

Why is a truck in 4x4 on the highway?

I see a lot of replies that are dropping the ball on this one.... SuperDuty ESOF is a lot different from anything I have seen discussed....

What is needed.... mileage on the truck when the failure occurred... and miles on the truck when the last spindle service was performed.... Many owners discount the importance of the large (and spendy) steering knuckle seals regarding proper 4WD operation.... The operation of the auto hubs is vastly misunderstood and, IIRC, I have posted on the subject before....

Having said that.... the failure you describe should have been accompanied by sufficient warning that something was amiss.... at the very least, there would have been a transient vibration.... Not necessarily a "distressing" vibration but it would have been something out of the "normal"....

Now...... if the truck will still move, modern logic tells us we can still drive it.... no matter how bad the concern - I'm not picking on you.... I'm talking about too large a percent of my customer base....

By your own admission, "This pickup has almost always seemed to bind in turns.". This is a sure sign that something is wrong. If, after your dealer said "nothing is wrong" and you felt that something WAS wrong... it is time for a second opinion....

Getting back to the hubs.... the hubs are not the weak point.... lack of proper service IS!!! Our shop is almost exclusively centered around SuperDuty 4X4s.... This system is virtually trouble free...... as long as proper maintenance is performed....

Your warning should be "perfgorm proper maintenacne"... not "this system sucks"..... After all... it worked great up until it didn't work any more , right?

The vacuum operated hublocks on Super Dutys are prone to early failure, I would submit that most owners don't ever touch them so they wouldn't know if they work or not. On my '02 F250, I had two hubs locks (both from driver's side) replaced under warranty due to failure to properly engage/disengage. The first one happened at under 20,000 miles, the second under 30,000. After warranty expired, they failed again at 45,000 miles and I had them replaced with Warn manuals. My current Excursion has had no problems yet, however.

I don't really understand the sequence of events here. Where exactly was this joint that failed? If you were driving with one hub locked in, or two, forever, why would any universal joint fail? I don't see the connection. Does anybody see it?

I have to assume that when you said crank case you really meant the transfer case. It's not easy to break that piece except maybe through failure of the frontmost u-joint. The joints inside the axle wouldn't explode anything if they broke. At least I don't see how.

I would agree with this. This is a very simple explanation, where the OP's explanation required a long sequence of events (made up, obviously) that don't seem to be plausible.

I know the system is not the same as an F150, - however, I can't see where having the hubs engaged should cause binding if the transfer case is in the

2WD position.

Here is what I think I understand -

A 2000 SuperDuty offered two 4WD systems - a manual system and an electric shift system. The manual systme has manual locking hubs and requires the transfer case to be manually shifted to 4WD. As long as the transfer case is not in 4WD, there should be no binding even if the hubs are locked. The electric shift system electricaly engages the transfer case. The hubs can either be in an automatic mode or a manual mode. If you leave the hubs in the automatic mode, then they are controlled automatically (using vaccum). When you shift the switch on the dash to 4WD the hubs and transfer case are engaged. You can also manually lock the hubs. Either way, unless the transfer case is also shifted to 4WD, there should be no binding.

Do you agree?

Ed

I think I agree with some other posters who suggested that you were in 4WD. That makes a lot more sense than your explanation. I don't think the hubs were at fault.

The problem with your explanation is that you made it up. After your tranfer case broke open, you surveyed this pile of parts and then made up a series of events to explain it. Right? You need to think about this. If you know what failed first, you should certainly say so, but I so no reason to assume that you actually know what the root failure is.

All true, Ed. The OP had his T case in 4wd, whether by ignorance or by truck malfunction. He may have thought it would be safer in the rain. I knew a woman who put her Jeep Cherokee in part time 4wd whenever it rained, she wondered why her front U joints broke...I told her she was lucky it was only that...

My guess. He pulled his pontoon boat out of where it was parked / docked in 4x4 , then didn't take it out of 4x4 and flew down the highway. the t-case exploded and took a cv joint too.

now he wants ford to pay

As far as I know, the vacuum is used to engage the hubs, the hubs are spring loaded to unlock. In any case, by your description, you hubs have been locked for a very long time. The failure mode is more often that the hubs do not lock when asked, your experience is opposite that of most people with problems in this area.

The result of your problem, exploding transfer case, is what I would expect though. (Your transfer case exploded, by the way, not the crank case.) Having said that, having the front hubs locked in 2WD would not harm the transfer case, transmission, or crank case.Lots of 4WD systems don't even have hub locks anymore, the front hubs are always locked and the 4WD system is engaged and disengaged solely by the selection of the transfer case. If the transfer case is not selected, the front tires merely turn the front drive shaft, but the front drive shaft is not connected to anything inside the t-case, therefore no damage is done. If your truck was being operated unknowingly in 4WD on pavement, then the tcase would explode. But, having the front hubs locked would not be an issue if the truck was really set to

2WD. (I've been operating my Jeep with the front hubs locked, and the tcase set to 2WD, for going on ten years, and there is no damage or ill effect of any kind.)

Your complaint that there has been noticable binding in turns (I assume parking lot manuvers and the like) is a sign that your truck was in 4WD. The front and rear tires on your truck will travel different lines when making a turn in a parking lot (they travel different lines in any turn, but you will feel this in a parking lot more than on the road), and the binding you feel is the front tires scrubbing on the ground to release the stresses of the turn.

The differentials accomodate the different arcs that the left and right tires travel in any turn, but the transfer case has no capacity to accomodate the different tracks of the front and rear tires. The result is that the transfer case gets stressed severely when the truck makes a tight turn on pavement. If the same turn was made on dirt or gravel, the front tires would slip on the ground and release the stresses, and you would not feel the binding that you felt on the pavement.

Your truck is equipped with Part Time 4WD, this means it is intended to be used part time only, it should not ever be used where there is sufficient traction (dry pavement) to hold the tires from slipping on the ground. You ought not even drive you truck in 4WD in the rain, and unless snow and/or ice is covering the roadway where you are driving, you should not use 4WD at all when driving on the street.

IKf you perform this test in 4WD on dry pavement, you should expect to feel binding and a wobble in the steering wheel. This is perfectly normal, and it is your sign that the 4WD system is not happy with the crap that you are making it do.

Because the operator is a maroon (sic), or the 4WD system is broken. My vote is the former ...