4x4 novice please educate me

[GeorgeN]

I have had my 91 explorer 4wd for 4 years and it is on 172,000 miles.
The 4wd has stopped engaging and all I hear now is a couple of clicks but nothing really engages.
I took it to the dealer and they want $600.00 (labor included)to replace the motor that engages into 4wd.
Since I consider myself a handy person I want to fix it myself but I do not undertand the process on how the engaging really works.
I have read some of the postings in the board and I see messages a bout taking the motor apart and cleaning it or
"auto hubs gone" and replaced with "manual hubs".

I guess my questions are the following and only because I do not understand the how's or why's.

If I push on the "4x4" button what takes place ? The motor runs and engages the 4wd? how does it interact with the auto hubs?
If I changed the hubs to manual. will the "4x4" button will still work ?

what do the manual hubs do?

Please forgive me for my ingorance but I will really appreciate if you are willing to pass your
expertise and knowledge.
Thanks in advance.

1991 explorer 4.0L v6 engine automatic trans :redexp: :redexp:

 

[X-1]

The shift motor that you asking about is located on the transfer case, when you push the button it engages power to your front axle. The auto hubs are really just full time hubs, basically engaged all the time, saving you from having to stop and get out to lock in. Part time hubs such as warn give you the option of running with out the front hubs engaged, also increase mileage a little due to the front wheels not turning the axle. Also good if you have a front locker, part time hubs are also stronger. The shift motor you are having problems with has nothing to do with hubs, I still run the auto hubs at 178,000 miles with no problems. If the 4 wheel drive has not been used often, it may need cleaning. I think if you search in under the hood section you will find more info on this subject.

 

[GeorgeN]

Great information and thank you. I think I will be working on it this weekend.

 

[TPLYNCH]

Just to clarify further... When you push the button, the shift motor in the t/f case moves and the t/f case locks. When it locks, the driveshaft to the front differential starts spinning, which in turn spins the axles to the front wheels. When the front axles spin, a cam in the autohubs lock, engaging power to the wheels themselves. With manual hubs, you eliminate the automatic locking (and inherent weakness of numerous weak plastic parts engaging) of the front wheels. With manuals, you can lock the hubs while not having the button pushed. I believe manuals also eliminate the need to reverse as you have to with the autos in order to disengage them. You still need to push the button to engage the t/f case no matter what hub assembly you have.

 

[AlaskanJack]

I had never owned a 4 wheel drive vehicle until coming to Alaska and the info given to me by others here is all I know.

My question for a 93 & 94 Ex.

1. Does it harm the T-case or ujoints if during the winter we leave the hubs locked in without the t-case engaged?

2. Are these years truely shift on the fly for engaging the t-case?

3. What is the max speed for driving in 4hi or with hubs locked in and t-case not engaged?

I know it may be alot but I just want to make sure that I haven't been given bad info by non Ford lovers.

 

[AlaskanJack]

The only reason I ask this is that after running last winter with hubs locked in and engaging t-case only when needed I now have to replace my t-case. And my wife's Ex needs u-joints in the front.

 

[SteveVB]

1) No

2)yes- my service manual says at any speed

3) same as 2wd as fast as the engine will push the vehicle.

You do add wear and tear to the additional componants that are turning in the front, but they are designed to turn so you are not doing anything they are not designed for. Doing anything at higher speeds adds additional loads and forces so wear and tear will be correspondingly higher.


What happened to your t-case? Specifically.
Anytime you run something it wears. U-joints and bearings in the front axle and transfer case- but they should not wear any faster than those used in the rear- matter of fact much less since they are not engaged most of the time.

 

[RangerX]

Originally posted by EXPLODER-1
The auto hubs are really just full time hubs, basically engaged all the time,

Not true!They are part time, same as manual hubs. They just engage and disengage automatically.

 

[RangerX]

AlaskanJack, if you been running in 4x4 on dry paved roads, that could damage the T-case.

 

[GeorgeN]

thank you

thank you very much for all the great info guys. I will find out if that is the problem this coming weekend when I work on it.

 

[X-1]

Okay now I am confused , Previous 4x4's I have owned that were what they call full time hubs, meant that the front axle was engaged all the time. On the explorer with auto hubs, how is the hub to know when to engage and when not to? As for shift on the fly, the manual says not to exceed 35 miles per hour when shifting, shifting at speeds faster than that can cause harm to t-case.

 

[TPLYNCH]

Originally posted by EXPLODER-1
Okay now I am confused , Previous 4x4's I have owned that were what they call full time hubs, meant that the front axle was engaged all the time. On the explorer with auto hubs, how is the hub to know when to engage and when not to? As for shift on the fly, the manual says not to exceed 35 miles per hour when shifting, shifting at speeds faster than that can cause harm to t-case.

on the '91-94 Ex, the following is true (to the best of my knowledge), and should answer your question.. When you push the button, the shift motor in the t/f case moves and the t/f case locks. When it locks, the driveshaft to the front differential starts spinning, which in turn spins the axles to the front wheels. When the front axles spin, a cam in the autohubs lock, engaging power to the wheels themselves.

on the '95+, the "hubs" are permanently locked, and the front driveline is always spinning (except for 95-96 with the vacuum engaged front differential).

 

[AlaskanJack]

Originally posted by TPLYNCH
on the '91-94 Ex, the following is true (to the best of my knowledge), and should answer your question.. When you push the button, the shift motor in the t/f case moves and the t/f case locks.

Okay so here is my next question.

I have a manual T-case so no push button, now is info still correct? Shift into 4 wheel drive at any speed.

I never drive on dry pavement in 4x4, maybe hubs were locked in, but T-case not engaged.

My T-case was grinding when I backed up without 4x4 engaged. Nasty noise. We lifted it off the tires and ran it in reverse then engaged the T-case and spun the wheels forward. It sounded like the gears were missing the wheels turned but there was a repititous clunking coming from T-case.

 

[X-1]

TPLYNCH

Thanks, that makes sense, I am still learning how different Fords operate compared to other vehicles I have owned.

ALASKANJACK, There should be a warning, or instruction decal on your visor explaining 4 wheel operation, I am not sure about manual transmissons. I do think that it is probably similar to auto.

 

[AlaskanJack]

EXPLODER1 - Well I have seen nothing on my visor referring to 4x4 operation, just mirrors on both visors and nothing on the little sunvisors behind the larger ones. My wifes 94 Xlt I don't believe has anything on her visors either. I will check both again just to make sure.

 

[X-1]

Alaskan Jack

I checked the Ford manual, and it say's that you can shift from 2 wheel to 4 wheel hi at up to speeds of 55 miles per hour. As far as hubs, it only states that keeping part time hubs engaged will cause higher fuel consumpyion, and increase in wear. Going from 2 wheel to 4 wheel may cause some clunking or ratcheting sounds due to front axle coming up to speed, but not cause for concern. This is not designated to any one system, general outline for either, auto, or manual trans. The sticker I was thinking of, was the warning about handling, sorry. Hope this helps.

 

[AlaskanJack]

Thanks that was the info I was given this past winter somewhat. I was told to not drive in 4Hi at speeds over 55 mph.

But it sounds like my source for information was fairly accurate in his statements even though he is a Chevy man.

He has way too much information floating around in his head. He can rebuild a motor, build a computer from parts, repair all sorts of machinery, build a house and design the roof trusses for it. Man I need to stick close to him in the event of a catastrophic disaster. He's McGuyver!!

 

[GeorgeN]

fixed my 4x4 problem

Thank you guys for all the info. This past saturday I got under my Explorer and took apart the motor that engages the front wheels and found out that the magnets were broken into pieces inside. Anyway, it was very damaged and could not be fixed. I got a new motor and placed it back where it belongs and WOW!!! ...4x4 was back to normal. I am now ready for the snow and mud.
Thanks again for all your help.

 

[Minivek]

Anyways, you probably shouldn't be driving around at over 55 mph if you're a situation that demands 4x4... One thing I did find out is make sure the back tires aren't spinning ( on ice for example) qhen you engage 4x4 on auto hubs... It makes a REALLY scary noise..... just my 0,02$

 

[MattPersman]

my question is why is it bad to drive in 4x4 on dry paved roads? say you are driving to work in mixed conditions never knowing when you are gonna hit some big snow drift or ice and want 4wd on?

what happens additional stress wise to the system if you drive on dry pavement? is it the transfer case I am guessing?

if you are offroad with your 4wd on there are going to be time when the tires are not spinning like dry pavement, does that do damage too?

I am new, 2nd year, to 4wd so I honestly don't know. I have known people that just hit the 4wd on and drive for miles on end if its snowing or the like outside.

thanks in advance