auto hubs

[pooll]

my 91 explorer has auto locking hubs my tranfercase and driveshaft work but my front wheels dont turn r auto hubs vaccumed or electronic there was a new computer put it but is was after market would that cause it i dont know about that plz any help would be good ty.

 

[mikeinri]

No, it's all mechanical.

The auto hubs need the wheels to be in contact with the ground, with the truck moving, to lock in.

Besides the transfer case, driveshaft and hubs, there are the front differential and front axle shafts that come into play (along with a few u-joints).

To diagnose this, put the truck in 2WD, turn off the motor, and jack up both front tires. Turn the front driveshaft by hand, and make sure the front axle shafts are turning (you'll need a helper to be able to watch all of this action). If the axles are not turning, could be your differential or u-joints. If the axles are turning, you may either have a hub problem, or a u-joint problem.

I once had a problem that I thought was the hubs, turned out to be the u-joints. My hubs were slow to unlock. I replaced the hubs first, didn't make the problem go away. I had the u-joints serviced, everything is good as new.

If your hubs have never been serviced (or not in a long time), try this first (it's a free fix). Remove the front tires, pull the hubs and spring-loaded cams (do a google search, there's tons of links to this procedure). Don't take off the rotors or anything that far.

Clean these parts thoroughly (get rid of all grease). There is a spring loaded mechanism within the hubs that must move freely (it engages the cam, it should be obvious when you have it apart). Make sure that mechanism moves in/out when you press on it. Fill the hubs with ATF and let them soak for a good hour.

Clean as much grease off the spindle as possible without removing any more parts. Drain the hubs, reinstall the cams, hubs and tires, take a test drive and see if they engage.

Sometimes, excess grease (and the dirt that it collects) makes the hubs have a hard time engaging.

If that doesn't cure it, time to look at the u-joints.

You could also bring it to a trusted garage and have them diagnose it. Stay with the truck and make them show you what they think is wrong (and why). Then you can decide if you want to tackle the job yourself (pay for the diagnosis and leave), or let them do it while you're there and the truck's on the lift in a warm garage...

Mike

 

[pugsy]

"The auto hubs need the wheels to be in contact with the ground, with the truck moving, to lock in."

CHECK - the auto hubs will engage with the wheels off the ground and still if you turn the driveshaft by hand.

 

[mikeinri]

If that's true, why do they not engage when you're stuck in beach sand, going from drive to reverse to get out? Been there, done that, it sucked (literally, sucked it right down to the rear axle)...

A friend of mine with the same setup on a Ranger said the front auto hubs need to have resistance to engage. I took his word for it, since I needed him to pull me out...

Other than the beach experience, I never experimented with it on jackstands.

 

[DeRocha]

If that's true, why do they not engage when you're stuck in beach sand, going from drive to reverse to get out? Been there, done that, it sucked (literally, sucked it right down to the rear axle)...

A friend of mine with the same setup on a Ranger said the front auto hubs need to have resistance to engage. I took his word for it, since I needed him to pull me out...

Other than the beach experience, I never experimented with it on jackstands.

Autohubs do not need any resistance to lock... If you have an open diff power will be sent to the wheel with least resistance. If both wheels are in the air the one with the least resistance (usually the driver's side due to its short stub axle) will begin to rotate and thus lock the hub... Once the hub locks the wheel has more resistance than the other wheel and so the other wheel will get power and also lock its hub.

 

[mikeinri]

Cool, good to know, very helpful for troubleshooting.

Of course, I still don't understand why I got stuck in the sand with the front tires not spinning when I tried to engage 4WD. Rears spun like a sad puppy. That was 7 years ago, and my 4WD has never failed me any other time (other than the sticking hubs I mentioned in the prior post), so I doubt it was the t-case or anything like that.

Could it be that because I was stopped in deep sand before I tried to engage the 4WD, the auto hubs were engaging and disengaging without turning the tires?

Mike

 

[old mechanic]

Unless the hubs are screwed up they should only disingage when you turn your 4x4 switch off and drive backwards for about 20'.

 

[DeRocha]

..Of course, I still don't understand why I got stuck in the sand with the front tires not spinning when I tried to engage 4WD. Rears spun like a sad puppy. That was 7 years ago, and my 4WD has never failed me any other time (other than the sticking hubs I mentioned in the prior post), so I doubt it was the t-case or anything like that.

Could it be that because I was stopped in deep sand before I tried to engage the 4WD, the auto hubs were engaging and disengaging without turning the tires?

Mike

Now I understand you question (the front wheels did nothing in 4x4)... If you engage 4x4 and the dash lights come on then power is absolutely being sent 50/50 front and rear.. The rear wheels don't have hubs to fail and are directly connected to the axle so @ least one wheel will spin in any condition. The front wheels are only connected to the axle via a locked hub. It is extremely common for autohubs to fail and prevent them from locking...When this happens the front axle will just free spin in the wheel whose hub hasn't locked. All it takes is one broken hub for the entire front end to keep power from reaching the wheels.

If your autohubs occasionally work then it could be a simple matter of someone over greasing them or inspect the hub splines for any burrs. Hubs are a dry assembly and only require a thing coating of grease; all too often people will pack (aka stuff to the gills) the hub with grease. Unfortunately this grease will hydro-lock the hub and prevent the inner mechanism from locking. See the repair link in my sig for related info on hubs etc..

 

[mikeinri]

RIGHT!

We sort of got on a tangent, so to go back to helping pooll with his original question, what DeRocha just said was exactly what I was eluding to in my original reply to pooll (remove and clean the hubs before spending any money on other repairs). Basically, everyone here agrees with that post except for the first line.

Having said that, should one expect to park a Gen 1 Explorer with auto hubs on soft beach sand in 2WD, engage the 4WD button, and have the front hubs lock and the truck will drive out of the sand? I thought the wheels had to be moving for the auto hubs to lock in.

Mike

 

[DeRocha]

...Having said that, should one expect to park a Gen 1 Explorer with auto hubs on soft beach sand in 2WD, engage the 4WD button, and have the front hubs lock and the truck will drive out of the sand? I thought the wheels had to be moving for the auto hubs to lock in.

Mike

Yes.. When you engage 4x4 the front drive shaft will spin and then send power to the axle shafts.. The axle shafts will begin rotating in each hub; after a few revolutions the engagement cam will have idle up within the hub and caused the hub to lock. Once this occurs on both hubs 1 wheel will get power and begin to rotate.

Let the above sink in for a minute.. If you try to free a vehicle by quickly going from Forward to reverse you can easily blow a hub.. When you reverse direction the axle shaft obviously spins in the opposite direction causing the hub to UNLOCK and then LOCK in the new direction.. Under low power this isn't a big deal, but if you're on the gas heavy it can definitely damage the hub... Manual hubs are either locked or open, as such would be unaffected by rocking a vehicle in the mannor.

 

[pooll]

ok ty all very much ur imfo will be very helpful, btw the back hatch will not open i tried turning the handle but it dont seem to turn any suggestions on this lol ty again pooll am i posting this right lol.

 

[mikeinri]

Never overlook the obvious, does it appear to be unlocked? You may need to crawl in through the passenger compartment to manually unlock it, worst case. I don't know of any way to open it from inside, unfortunately.

Mike

 

[Mud Bug 94]

does theglass open?

 

[pooll]

no the glass nor the hatch open at all the handle seems to be very tight only turns alittle to the left.

 

[pooll]

91 ford ex for sale 900$ needs some work but driven everyday this is the 1 that needs hubs transfer works really good has some rust but not alot just bought a 94 dont need this 1 am taking it to the mason dixon auto auction tuesday of next week unless some1 wants it ty.

 

[DeRocha]

As others have asked is the LOCK on? Does the lock rod move up and down freely? The rod mabe slippery so you may need to grab it with leather gloves or pliers...

 

[pooll]

i havnt checked to see if it was unlocked lol but i will go check it if thats unlocked any suggestions on how to get the panel off without opening it

 

[DeRocha]

i havnt checked to see if it was unlocked lol but i will go check it if thats unlocked any suggestions on how to get the panel off without opening it

The lock solenoid could have failed preventing the door from automatically unlocking.. Simply pulling up on the lock rod should do the trick.. I believe there is a small access panel @ near the rod that can be removed to gain some access, but you should 1st check and see if its locked 1st

 

[pooll]

ok ty i will check it.

 

[pooll]

i just bought it saturday i had no heat slide the cold and hot air bar back and 4th a few times heat started working but now it dont again lol