Resident experts,

I just bought a 1997 F-150 that won't engage the 4x4. The indicator lights show both "4x4" and "4x4 Offroad" when the shifter is in the appropriate position, but the front wheels won't lock in. I've read a little in a repair manual about testing the vacuum pump, etc. but want to hear a few recommendations as well as similar ventures before I dig in. I'm pretty frugal... okay, a tight wad, and don't want to fork over the cash to a dealer. I'd rather have some fun working on it and fixing the problem myself. Any advice?

Thanks...

 

Sorry.. not "Off-Road" but "Low Gear."

 

Well for starters you can give the forum some info about how you've determined your hubs aren't engaging. Then we can work things out and try to get your problem solved.

-Kerry

 

Thanks...

I spent a lot of time reading other entries with the same symptoms and most seem to be due to hubs engaging. I'm afraid mine might be worse...(BTW, this is a 1997 F-150 4x4 w/ manual tran.)

The truck runs fine in 2H, but in 4H the front wheels aren't pulling. In 4L, the smaller gear engages the rear wheels but not the front.

Last night I put the truck in 4H. The indicator light read "4x4" but I'm not sure if the click I heard was just the shifter or the transfer case. Anyway, I got under the truck and marked the front axles with a Sharpie. I started the truck, put it in reverse, and came back about three feet. Again, I looked under the truck and the marks had moved. No problem, right? Well, I repeated the process for 2H and the same thing happened, the axle moved with the wheels.

So I jacked up the right front put the truck in 2H. When I spun the tire, again the axle moved with it. In 4H, the same. In 4L, the same.

Does this sound like the hubs are siezed up or more like a transfer case issue?

 

The automatic "hubs" really aren't hubs in your truck. It actually has an axle disconnect in the front differential. If you take the hubcap and dust cover off, what you will find is a flange. The axle always turns with the wheel. Have you tried it off road, or in the snow? Try getting into a low traction situation in 2wd. Don't bury the truck, but get it to the point it will spin the tires. Now, stop and lock it into 4wd Hi range. Does it just spin? Then 4x4 is not engaging. If it pulls itself out, it is working.

Jared

 

Without getting yourself buried is one way to check...kind of need a buddy there if you stick it in too deep or the 4wd is screwed up.

I'd just lock the truck into 4HI, drive it into a parking space (about a 15 foot drive is fine and should lock anything up), shut it down (you have a floor mounted 4by shifter, right?), block the rear tires, put the truck tranny into neutral then you'll be forcing against the other tires if everything works, not against a gear (although you can do that too and accomplish this test). Jack both front wheels off the ground, and check to see if you can freely rotate both front tires by hand. One side may roll freely, but the other should lock up, as you most likely have a non-locking front diff.

I am new to these types of 4WD systems as I just bought a 2000 not that long ago, so if anybody sees a flaw in this train of thought be sure to pipe up.



-Kerry

 

I usually do the spin test Ford_Six described, but if you want to do it at home, just put it in 4H & lift ONE front wheel. If you can spin it more than 1 rev, then the front axle didn't engage.

 

Thanks for the info... I didn't know the 97+ came without hubs.

So I'm driving in the ice/snow and attempt to put the truck in 4H. Indicator light, click, etc. all sound/look good. But a friend watches the front tires while I give it gas. The rears spin, but not the fronts.

Obviously (supported by Jared's diagnosis) the 4x4 isn't engaging. But where does it sound like the problem is? Transfer case? Dirty gears? Dealer or doitmyself? Has anyone seen this on a 97+ truck?

Thanks again guys,
Jonathan

 

I believe with this type of system if you're not rolling it won't engage fully. Like I've said, I've not worked with this particular type of system. I do know that with other systems with auto hubs and the like, if you're not rolling it won't engage.

My advice is to try a jack up and rotate test first before you start thinking you have a mechanical flaw. Make sure the system is not engaging. The only way I can think of is to engage it, drive it a short distance, and then jack it up and check for rotation or lock up.

If you do have a mechanical flaw, and this is a center disconnect style system, it will be in one of two places: the t-case or the diff as you have no hubs. In other words, somewhere in that area of the front shaft would sound resonable.

Does it grind? Are you only attempting the shift when you start slipping?...which would break things in the system, as parts would be moving faster than others then suddenly have to be moving at the same rate...crack!

I'm sure that, since this doesn't have hubs and you hadn't mentioned any noise, it's gotta be working or someone has removed parts. I say that because the system seems to be virtually mechanical in nature and when things like that break, they let you know.

-Kerry

 

[updated:LAST EDITED ON 10-Dec-02 AT 11:03 AM (EST)]I have a 98 F250 light that I am having the same problem with. It engages sometimes, but not others. When it is engaged (you can tell it's working during turns etc) the light is still not on. When you stop (apply brakes) the light comes on and you can turn the system on and off. Sounds crazy and it is, It is about to drive me nuts... I am contemplating changing to manual hubs...

 

If my understanding of the '97 and up F-150/F-250LD 4x4's are correct, you can't just swap to manual hubs to fix your problem in any case. After reading through these posts and conferring with other '97 and up F-150/ F-250LD owners, I have come to the conclusion that if the 4x4 system doesn't work, the problem won't be at the outer ends of your axles.

First off, if you have the switched electrical type of t-case, you have that to consider as a problem. Generally the electric motor that drives the mechanism will ether blow fuses or just quit working. Nasty little habits and it's been like that for as long as I can remember the push button/rotary **** systems being around.

Secondly, since this is a center disconnect type diff system (and I use that term loosly, as center disconnect is actually used to describe the t-case types) all of the components necessary to lock you into 4x modes are located either in the t-case or the front diff...not the outer sections of the axle.

What does this mean? Well it means that unless you intend to throw a completely different type of set up under your front end, or somebody engineers a very expensive kit to change the lock up from the diff to the hub ends then you aren't going to swap a whole lot of anything.

Perhaps well all learn a little more when we get a guru of these systems to post more about the secrets of this style of 4x4 system

Sorry I couldn't help you guys more.

-Kerry

 

Okay... round 2.

The 4x4 needed a slow roll to engage. I can now feel the difference when turning (small hops) and climbing small hills. However, sometimes it will disengage with a medium-loud pop. This occurs when climbing a hill too steep and sometimes even when turning.

I'm thinking I need to open up the transfer case and check the gears for damage/too much sludge. Does this sound like the right train of thought? Anyone done this before?

(1997 F-150)

 

[updated:LAST EDITED ON 30-Dec-02 AT 06:17 PM (EST)]yo guys; this info is crashz:
"Actually the 97 to present 4x4s do not have hubs at all. They have a central axle disconnect which seperates the wheels from the gears and driveshaft.

First check the linkages from the lever to the t-case. These are notorious for rusting up and making it difficult or impossible to shift.

If the linkage is free, you may have an issue with the syncros in the t-case. These allow the case to be shifted at any speed. Will the case pop into 4x4 if you slowly roll ahead while pulling on the lever? Have you tried putting the transmission in neutral and then shifting the case? If not try these and let us know what happens."

 

[updated:LAST EDITED ON 03-Jan-03 AT 04:50 PM (EST)]I am having the same problem with my 98 F-150. I can tell that my problem is NOT mechanical. It is either the switch on the t-case lever that triggers the vacuum solenoids to engage the front axle or the solenoids themselves; I haven't figured out which, yet.

This is really irritating since I don't like all of the fancy electrical/automatic junk. I thought I avoided some of it by ordering the floor shifter in lieu of the dash push button.

 

Does your 4x4 'pop-out' on hills or tight turns?