I get a clunking sound while driving in forward, there's something going on in my front end.

I can turn the driveshaft about a half turn, then it takes some force to move it a bit more, then it will turn easily another half turn. (At the point of force, I hear the clunk). I can see some front end part moving through a hole, like the axle or something?

should the front driveshaft be engaging this axle that turns with some resistance?

i hope im making sense.. let me try to clarify in case im not

-the front driveshaft turns when in 2hi while driving..
-when turning by hand, it spins but with some resistance.
-I can see the axle or something (i have little experience with ttb) move when I turn the front driveshaft. The front axle locks about a half turn of the driveshaft, then spins freely a half turn, then locks a half turn. It's through some hole on the passenger side of the vehicle. It's noisy when it locks and it can be done with both front wheels on the ground.

would this possibly be a single locked hub? with either tire jacked, it moves freely but I've not tried with both sides jacked up.

also, could it be a broken axle or something? my 4WD, when engaged in 4HI, makes a scraping sound out of the passenger side wheel, but this sound isnt there in 2hi.

i get a noticeable dragging feeling while driving that isnt there in reverse.. and I think this all started after I got the bronco and shifted into 4wd to check it, the guy I bought it from hadn't been using it.

 

Are your hubs the factory automatic? If so, there is a good chance that they are shot. The factory auto locking hubs were not designed for heavier off road use and will wear out in short order. Seems they must have been designed for the yuppie's occasional "let's use 4x4 in the once every two years snow" excursions. The metal "clunk" sound is really hard core and you will think that your Bronco is fixing to go down hard. The prior owner probably did not have a clue..or hoped that you didn't.....

Consider switching to a manual hub..like premium gold Warn etc. (No advetisement) Doesn't cost much and your 4x4 will be more reliable.

 

I plan on it in the future, but for now I have other priorities.. I might just pull the hubs off of my 80s to get me by.

do hubs work by pushing the axle, or clutch or something at the axle inward towards the diff? If so, it would make sense that they're partially engaged on the passenger side. I just dont see why the passenger wheel would spin freely, but the driveshaft would be stuck turning the axle with a locked hub, that's what's confusing me about this.

 

Automatic means if you apply torque from the diffs to the axles (via pressing the dash button), the hubs auto engage via a spring. If not, they just roll free. My understanding is that some of the auto hub enternals are plastic....not positive though, I paid to have mine done. Manuals "manually" do the engaging of the axle, and you can leave them engaged and still ride in 2WD if the weather is bad, and change on the fly from inside as needed. (You can feel the axle turning, but the load is not too awful bad.) Get out and twist them out when weather is good..... Advantages and disadvantages to both, but most Bronco owners end up going manual at some point for the peace of mind of knowing that they have manually twisted them in for strength and confidence.

For what it's worth, you can have the job done for less than a $100 bucks. I paid less than $40.00 for my hubs several years ago and my mechanic charged me $25.00 to put them on....(worth the extra trouble to me at the time....now $$ is tight!) This was after the auto hubs went out on a ridge in WV...made it down but the noise was incredible.....then the learning began...from a Chevy guy

 

well, i have no dash button. it's the manual tcase (which I love), i assume the hubs lock in some way when you manually shift the tcase. i dont like automatic hubs, i never have, and will eventually replace them.. but if I can put the money in other areas i'd rather do that for now. I cant justify spending any real money on myself or my vehicle this time of year

im gonna try pulling the passenger hub tonight and see what im dealing with. i've cleaned manual hubs and it made a huge difference.

wish me luck.. and if someone has any other ideas, i appreciate it.

 

my bad on the button...when you shift to 4HI/LO energy is transferred to the front axles (via the front driveshaft). For auto hubs, the subsequent torque engages the hubs using a spring type spline mechanism. With manual, you are physically twisting/turning them in and locking the hubs/wheels into the axle. Unless I'm missing something, I'm sure that one auto hub can go bad, or get dirt in the spring etc. or just strip out as mine did.
If you half know what you are doing, you will at least end up with a repacked bearing out of the deal..

 

The metal the outside casing rests on is loose. I pulled it, checked it out but because I was cold I just put everything back the way it was.. in the process, I broke off a torx bit in one of the screws.

im gonna go try to find a diagram of the auto hub, I couldn't get it apart (but again, didnt spend that much time on it).. now I have to drill a screw though.

edit: I can just pull a manual hub off of the 1980 bronco I have, right? or the 78 f150 (d44 front) ? I'm pretty sure I can, but it doesnt hurt to ask.

 

The auto hubs rely on centrifugal force from the axle to engage. As they age, they tend to engage late and disengage next to never. Regardless of how they work, in 2HI they should NOT be engaging whatsoever. End of story. If they do, they need to be serviced (which I personally would not waste my time doing) or replaced with manuals.

 

I believe this is the first time I have cought Greystreak being wrong. Sorry Greystreak. The auto hubs do not relie on centrfugal force. They will lock at a crawl.

They lock from the axle turning at a differnt speed then the spindle. (which is always zero) Not to be confused with hub speed. (speed of the wheel) The hubs will lock in one direction (either forward or reverse) This is not to say that if locked in reverse it wont go forward in 4WD. (it will) It's just that to unlock the hub, it must be unlocked oppisite of the direction it was locked.

It is very possible to have just one hub locked and can be difficult to unlock it, especailly if you have a locker or limited slip in the diff. What will happen is while the one hub is unlocking, it is turning the other axle, locking that hub. In some cases you must jack up the locked wheel and free it by hand. To avoid this situation, make sure you unlock the hubs in a straight line at least twenty feet.

It is a very poor design and a week design. This is one issue that almost all on this forum agree. (thats rare) Go manual. You can use hubs on some of the older trucks depending on the bolt arrangment.

 

ill definitely switch to manual..

Ok, I need to back up for a minute if you all dont mind helping more.

the front axles should always spin when I turn my front driveshaft, correct? I unlocked the passenger hub and it worked, it doesn't bind up at all when I turn my front driveshaft, but the front axles do move.

also, there is play at the end of that axle, I can move it up and down and side to side, I have a feeling that's not normal. The hub itself also had this play and the one on the driver's side doesn't. I wonder if it's that locking C-Clip at the end of the axle? this is the first ttb or automatic hub I've messed with, anything prior has been 1980/79/78, etc and earlier.

 

Not really my area but:

As you probably suspect, sounds like a bad wheel bearing. You don't really know how the previous owner used the vehicle. If he went off road a lot, through deep mud and water, over time stuff can work it's way in there.


My Warn instructions say to re-pack the wheel bearings every time that the truck is used in those type of conditions, which few folks ever do.

Probably for warranty reasons.


Is there noise/humming or grinding when you drive? Does the sound lessen or go away when you steer right or left?

If you change the bearing, do both sides.

 

helirich,

My description was incorrect. The term "centrifugal force" and my description is indeed inaccurate. Your description of the hub operation is correct. Apologies for any confusion.

 

"When torque is applied by the driveshaft, it forces the hub to slide in and lock. The hub then remains in the locked position as long as the transfer case remains in four-wheel drive. When the driver shifts to two-wheel drive, the clutch mechanism inside the hub slides back out and releases the hub, allowing the wheel to turn independent of its axle shaft."

or:

"The spring-loaded hub automatically engages on the fly when the transfer case is shifted from 2WD into 4WD. The application of torque to the axle causes the mechanism inside the hub to slide in and lock."

Adapted from an article written by Larry Carley for Brake & Front End magazine


That's my story and I'm sticking to it!

 

I'm not sure where this play is, but it sounds like that is your trouble. There is a set of neadle bearings in the spindle that locate the axle in it. Not to be confused with the wheel bearings on the outside of the spindle. One thing I'll mention. There is only one c-clip on the TTB. It's on the pax side axle. It is a pain to remove this c-clip. Sometimes it is easier to remove the clamp on the rubber boot and slide the half shaft out if you need to work on it. (such as u-joint replacment)

 

any advice you can give would be appreciated, like I said, I've never dug into one of these TTB front ends.. and I even have very little experience with solid axle front ends.. it just seems like when I hit frontend trouble, I move onto another vehicle (front end isnt what puts me off, it just happens that way)

I know I'm going to have to dig into it and learn a lot of it as I go, but any advice you can offer would be great, this is definitely my weakest point with vehicles.

Just to clarify where I'm at.

I removed the front hub to test drive, the problem seems to have gone away with the partially engaging hub. I just capped the hub.
The axle with the hub installed or taken off, has some play at the end. I can wiggle it around easily.

I made a promise to someone that I loved them more than I love my Bronco (at least my Bronco doesn't get jealous!), so I had to take a break from working on it today.. it rained anyways, so I couldn't do anything even if I was allowed to.. I sorta cheated though, I got a new set of tires on it.. technically I did what I was told, all I did was drive it to the shop

I've never done bearings.. the inside of the hub looked packed full of brand new grease, so it looked liek the previous owner tried to trick the hub into working and he himself knew there was a problem..
I guess I could have suspected in, when I asked the guy I bought it from if the 4WD worked and how to engage the hubs, he gave me some kind of akward response along the lines of "The guy I bought it from said it works ,to engage the hub you have to take this hub off and do something"
Thinking back on it now, it sounds like someone gave him instructions on how to repair it and he mistook it as instructions on how to lock the hubs for 4WD..

The guy I bought it from only had it for a little while and was trying to learn how to do repairs himself, without much luck, so I wasn't able to learn much from him.