Repair AutoHubs on '91-'94?

You find them let me know. I like manual stuff...but it would be handy not to have to get out and engage/disengage them when I need them.

I prefer manual too. I'd like to replace the electric motor that engages the transfer case with a lever. Is this possible? ('94 XL automatic trans.)

I prefer manual too. I'd like to replace the flaky electric motor that engages the transfer case with a floor lever. Is this possible?

I have yet to see a source for any internal parts for the auto hubs. Driving with the manual hubs locked in but the transfer case in 2WD isn't harmful. Before my current SuperCrew, it was the norm in my house to lock in the hubs when winter came and rarely unlock them until spring. Gas mileage takes a bit of a hit but if I were worried about gas mileage, I sure wouldn't have a

4X4 much less a truck. The oil pump in the transfer case is turned by the rear output shaft so there is no danger of lack of lube. One caveate.... if you have any loose u-joints in the front driveline, be they axle joints or driveshaft joints, they WILL beat themselves to an earlier than expected death.

Not to tell you how to run your house (but its coming, anyway...).... Mrs mechanic knows EXACTLY how the scene will play out if she doesn't pay attention to the instrument cluster and what it is trying to tell her on a regular basis. We tend to give our cars pet names and "personalities" (that may be true to a point but it has little to do with relationships), forgetting that they are machines... machines with lights, guages, dipsticks and sight plugs that need to be looked at...

That's good news. For sunny days my wife got a Nissan Frontier with a 4 cyl engine and 5 spd manual transmission. That one we bought for the gas mileage ;-)

When looking at the auto hubs I can't "see" anything wrong with them, other than the fact that they no longer lock. I can't even see how they are supposed to work. Nothing is broken and nothing appears to be worn or stuck. It seems like one day they work and then suddenly they are only good for pencil holders on a workbench. What makes them lock onto the axle? Is the axle actually moving into the hubs when 4X4 is engaged?

Later that day...

Here's what I did to determine if the auto hubs were bad: First I marked the front driveshaft and axles with chalk to verify that they were turning while in 4WD. All checked out OK. After having driven it a ways in 4WD I jacked up one side and tried to turn the wheel. It was solidly locked on the axle. I then jacked up the other side and it was trying to catch but not quite making it. So, assuming that the front differential slips under no traction situations and would prevent the good hub from turning this would in effect render the truck to be 2WD. Is this correct?

Maybe I should have payed the extra for faster shipping on the Warn hubs....

>

The term "differential" should be the clue... this allows one wheel to spin at a differnet speed than the other while still providing power to both.

should help. On the old Exs,pushing the button engaged the transfer case but NOT the hubs.... these workon an over-running clutch principal. If the front wheels continue to turn atthe same speed as the rear wheels, the hubs will not engage. However, if thefront friving axle spins faster than the front wheel, the hub should engage.We need to remember that these hubs are pretty low on the evolutionaryscale. They were early attempts to make motoring easier for the generalpopulace and entice non-machine people into more comples machines. Turning the wheel by hand with the driving axle stationary will have no effect.... a faulty hub is a faulty hub and any number of symptoms can appear.

Thanks for the link. I'm reading it now :-)

Well, I have a different opinion. I like autohubs - really convenient. Hate getting out in snow to flip the levers on those manual things.

The manual hubs will be inherently more trouble free if you tend to not take careful care of the automatic ones. But I would much rather press the button, here it engage, then feel the wheel lock. I think its kinda cool.

As for how they work, well these things are really clever and you kinda have to have a mind that can visual machinery with three degrees of freedom. But when you do figure it out, you'll feel good because most who try, never do.

As for parts. We have a couple of 4WD shops here in town and none of them know anything about autohubs. That's a good thing because they are always replacing perfectly good autohubs with manual ones. Most shops throw the take-offs in a corner rather than throwing them away. Just go ask. I purchased 6 sets of auto hubs for my Ram Charger (more than a couple of years ago) for $20.00 Ended up with a lifetime supply of parts.

I expect to do the same for my Explorer and similarly end up with a lifetime supply of parts. Just look around and ask.

I LIKE the autohubs just fine when they are working but they tend to quit working rather suddenly with no warning (not that I could tell anyway). We bought both of our Explorers used to I suspect the previous owners may have mistreated the hubs possibly leading to failure. But since so many people's autohubs have failed maybe they all fail after a time.

I'm not quite sure what you mean about "three degrees of freedom." Do you mean that there is 3 degrees of play between the hubs and the axle before they engage, or is this an esoteric philosophical zen kind of thing where the hubs reach different levels of conscienceness? Or perhaps I need to achieve the next level of conscienceness in order to understand the hubs? If a hub locks on an axle, and nobody hears it, did it really lock?

Are you able to identify worn or faulty parts within the autohubs and repair them? I had a part that goes on the axle that the hub fingers fit into that was cracked. I replaced it and it made no difference. I cleaned the hell out of the mechanisms inside the hubs and still no difference. I can see nothing (else) that is worn or broken. Are they subject to very close tolerances that need to be measured with a micrometer etc?

You are asking more questions than I have answers at the moment. I haven't taken my autohubs apart yet but I expect to in the next few weeks. At that time, I suspect I'll know a lot more.

Three degrees of freedom - well you have the axel shaft rotation, the wheel rotation, aqnd the stationary hub. The rotational relationship between all three determines the behavior of the hub. Very difficult to visualize unless you do this sort of thing all the time.

I suspect theat there are wear parts - but again, I'll know a lot more in a few weeks. I'll let you know what I find.

G

Professor is, obviously, well versed in academia as applied to physical states..... His three degrees refer to the different conditions met at your front hubs. The spindle is a constant.... it does not rotate. The drive axle can either remain stationary, rotate faster than the wheel assembly or rotate slower than the wheel assembly. The wheel assembly can rotate faster than the axle or slower than the axle.... again, the spindle remains stationary.....

There is nothing magical about mechanical actions. There are many things that the engineers have devised that are nothing less than amazing but logic is the driving factor in all of these forces (things change when electronics are introduced).

There ae many pattern failures regarding te early Explorers.... it is not uncommon to find someone bound and determined to reinvent the wheel. While simply replacing the offending assembly is quite easy, many prefer to avoid contact with their family and spend time finding out what so many before them have learned... it ain't worth the time...Bite the bullet, replace the hubs and go smoosh up to your loving bride...

Yea... I said "smoosh"...

I thought it may have been worth a shot to see if the autohubs could be repaired but I did like you said and put on Warn manuals and went and smooshed my wife (at least I think it was smooshing). Now I seem to have

4WD only sometimes on my '92. There is a lot of play on the drivers side front axle and it goes "clunk" while making left turns in 4WD. It seems like sometimes only one of the front wheels is engaged and it seems to vary. Too much play in something in the front differential perhaps? Or maybe I just need new wheel bearings? They looked OK when I replaced the hubs but I neglected to check for play in the bearings (rush job).