The truck is a 4wd 1986 f150. I have been having trouble with my front end ever since I slipped the wheels on some ice. The front tires were slipping on ice and then they grabbed. Ever since then I have been having a humming noise while driving around. I replaced the hubs with Warn standard manual hubs, but the noise is still there. What i find funny is that if i drive around with the hubs unlocked and try to engage 4wd in the t-case, it makes a weird clicking noise or almost like a shattering/grinding noise. The truck seems like it is not coasting very well because I lose speed rapidly and it is getting very bad gas mileage.

4wd does work very well, but it doesnt disengage like it used to. I used to be able to just push the t-case out of gear, but now i push it out, and I still hear everything moving in the front end, but I think the wheels are still spinning. I tried getting out and setting the hubs to free, but everything still moves, I think its the t-case making this noise. Also another way that i think everyhting is still moving is because when I turn on dry pavement it binds like when it is engaged into 4wd.

The only way I have gotten it to stop making the noise was to disengage the t-case and the hubs, and then drive in reverse for a short distance.

I just purchased the truck a few months ago and am not experienced with them so sorry for the ignorance.

Any information is appreciated. Thanks

 

Are you saying you're trying to move the transfer case shifting lever while the vehicle is moving?

-ct

 

You cannot "shift on the fly" unless the front hubs are locked in. If the front hubs are not locked in, then nothing is turning when you go down the road, so if you try to engage the t-case, it will grind, since it has no way to enagage something that is not turning, while it's spinning.

If you want the ulitmate fuel mileage, you need to unlock the hubs, and put the t-case in 2wd. Backing up to unlock it, or having to drive a couple of miles before it unlocks completely is normal. The spring in the front hub does not have enough power to push the lock sprague out unless the strain is relieved on the system.

If you want 4wd convenience but less fuel mileage, then lock the hubs in, but leave the t-case in 2wd unless you need 4wd, and then you can pull it in or out anytime.

Of course there is no purpose in pulling the t-case in 4wd with the hubs locked out. That's just wasting gas.

 

You most definately can put into 4hi when moving regardless of hubs engaged or not
of course it's not going to pull but the x case doesn't know wether the hubs are locked
or not. You only have to drive in reverse to unlock a auto hub equipped truck.
Change out all your fluids, X case, front diff and grease the front bearings. A little
test to see if you are having parasitic drag is to wrap some electrical tape around
the front driveshaft and tie it to the frame, with the hubs unlocked and in 2wd go for a drive Check after a 1/2 mile and under 30mph, still attached? go for a few miles and
up to say 70 or so. If it is still attached to the frame then you have a pretty free drive
line. You can do the same for each half of the front axle shafts and engage one hub
and then the other to be sure they are engaging and disengaging. How was the grease
in the front bearings when you did the hub? did you throw some in there when you had
it apart? I would most definately regrease and change out the fluids if it hasn't been
done or if you don't know when it was done!! Most people forget to grease up the front bearings on a regular basis since it seems like a lot of work or that it doesn't
need to be done for some reason or another!!

 

You say it clears after reverse, did it have auto hubs originally? If so did you install the conversion kit as well when you put the manual hubs on it?

 

I did not grease the front bearings when I changed the hubs, but now I wish I had. I took the truck out the other day and tried to switch into 4wd with the hubs unlocked to test it again and heard a scary bang at first and then a continuous clicking like I had explained earlier. When I first got the truck if I would do that nothing would happen. Thanks for all the advice. And no it was originally with manually locking hubs.

 

Just because it worked that way before you changed the parts and now it works differently doesn't mean it was working correctly in the first place, maybe something was broken before you bought the thing which became "normal behavior" in your mind. I have never tried to shift into/out of 4WD with the thing moving as such a thing wasn't possible when I grew up (or so I seem to remember it) but if I were you I would follow the instructions (s/b on the top side of the driver's sun visor and in the owner's manual). A humming noise, could that be the tires on the pavement?

-ct

 

On my 86' models, as well as other brands, with manual hubs / non electric transfer cases, I have never been able to shift into 4WD Hi range without the hubs locked in when moving.

This is how the Ford sticker also read on the sunvisor on both of my 86 models.

The reason why - there are no "syncros" in the transfer case and both driveshafts HAVE to be turning at the same speed, or very close to get into 4WD Hi range. (obviously this only applies when moving)


At least this is the way that it has worked for me for 30+ years.

David

 

I wasn't going to get into a argument on here when bluebeast wrote in with his comment, but maybe I should have, since you can definitely ruin something by trying to pull the transfer case in while moving with the hubs unlocked. Sounds like you tried it, and now you know.

 

OK well thanks everyone for the advice and sorry for the ignorance. I have heard many opinions about shifting on the fly. What is the real deal with this? I have done it before and it seems like it goes in fairly easy, but like Franklin2 said, once I shift out I have to drive for a little bit before the front wheels stop spinning. If you cannot shift on the fly then driving around with the hubs locked seems pretty dumb if you cant just engage 4wd. Thanks

 

There are some versions of the 4wd drive system that make it more user friendly, but they have more parts to break too. They had a pushbutton system that would let you enagage 4wd on the fly, even if the hubs were not locked in. It used a motor instead of a floor shift to enagage the transfer case, and it had a special transfer case with a internal electric clutch. This clutch is a key piece you are missing, as when it's activated, it slowly brings the front driveline up to speed before it enagages the transfer case. In conjunction with this they used auto locking hubs, that locked in when the front wheels started turning slower than the driveline(ie when the rear wheels started to spin). It used a computer module to co-ordinate all this.

That system works fine and dandy when it works. But when it breaks, you are in for a steep repair bill for troubleshooting and replacing expensive parts.

That's why most people who depend on their 4wd, don't mind getting out and locking the hubs in. Most of the time you can predict when you are going to need 4wd, so you can lock the hubs in before you take off.

 

Shift on the fly works fine, into 4wd Hi if the front hubs are locked in. That is the way it was designed to work. It actually makes no sense to be able to shift into 4wd if the hubs are not locked - what would the purpose of that be? It would be of no benifit to the driver, as you would still only have a 2wd drive truck with just more parts rotating.

Much better to pre lock the hubs - then you can go in and out of 4wd HI as the need arises, such as when you are on pavement that has occasional ice/snow patches - keeps the driveline from winding up when you are on the dry pavement areas. This makes the most sense from a actual 4wd Hi range usage.

David

 

Xfactor.. read up a little on this stuff. You are scaring me with your mode of operation. Just like dmanlyr said, what would be the purpose of shifting to 4wd if the hubs weren't locked in???? You have no 4x4 by doing this. Absolutley do NOT try and pull the truck into 4hi with the hubs unlocked. It will bang and click and ruin your transfer case. That is not the way it works! I think you proved that. When you actually put the truck into 4x4 (with the hubs locked!) and then take it out of 4hi, the front drivelines will still be turning and wasting power and fuel. Get out and turn the hubs to free. Then back up 100' and the hubs will dis-engage. This is a very common procedure on the older trucks. I do it every time.

 

Ok thanks for everyones help!! I have another question about using 4wd Lo with the hubs unlocked. I have read in other posts about people using 4w lo just to make it easier if you have a manual trans. They said that it wont hurt anything to use it with the hubs unlocked for a little bit of time. Is this true? Again thanks and Skoiv don't worry I wont try to engage 4wd without the hubs locked again.

 

You will have similiar problems. Just make sure you aren't rolling and better yet, turn off the engine, and put it in neutral or park before pulling it into 4hi or 4 low. You should still just turn the hubs in before going into 4low. Sometimes mine doesn't even want to go in 4low with the hubs locked. A few times I had to turn the engine off before putting it in. Results will vary between trucks. 4low requires that you are in neutral or park. Remember!