i can hear the 4low engage and works but if i put it in 4high the weels dont engage but the light comes up but no powere in the front wheels at all what could it be ? transfer case? transmission? or sensors or what please help or give any ideas anyhting could help thnx

 

What Year Vehicle.

 

its a 1995Explorer 4door V6 4.0L hmm i dont know what transmition model

 

i think transmision model is 4R55E so any ideas?
thnax

 

I have a similar problem on my 96. I would also like to hear some suggestions. It shifts fine into either hi or low, but the front tires won't spin unless I hit the pedal hard, it will catch after a second. I tried climbing a hill and the front tires never moved.

Help us please..

 

'95 and '96 (and maybe '97) have a vacuum actuated disconnect on the front differential. If that vacuum has ruptured/came off/ has a leak, it would prevent power getting to the front wheels.

 

I Agree,

I think the front end vacuum shift is not working. Look on the passenger side of the front axle. You should see a Vacuum Shift motor with two Vacuum Lines coming out of it. Follow them up to the Vacuum Shift solenoid and make sure they are in good condition.

The fact that your 4wd light is staying on means that your computer is satisfied that both driveshafts are turning at or near the same speed.

 

also for the 4wd system there is a TOD(torque on demand relay) that might be bad


I'm Glad I could help.
I had a problem with my transfer case. the Ford dealer gave me a qoute on $1750 to replace the transfer case. I felt like the symptons didn't match the diagnosis so I was forced to learn how the 4wd system works on a 1995. the result was that I changed a $30 speed sensor and now my system works fine. (and I learned quite a bit about the 4wd control-trac system.
Here's the $5.00 tour of your 4wd system.
1. PCM
The Powertrain Control Module (PCM) is the main computer for your car and also controls the engine and Transmission. the PCM is mounted on the engine side of the firewall in front of the passenger air bag.It is not serviceable but is very easy to change ($300.00). It is notorious for going bad at about 100,000 Miles
2. transmission.
This transmission is all electronically controlled. It is controlled by the Powertrain Control Module (PCM). It is also known as a weak transmission looking for a reason to fail. I had mine fail on me and it cost $3,000 to rebuild
-GET a Small external tranny cooler and have it connected in series with the existing cooler so that the engine pumps the fluid through the original cooler first, then the auxilary cooler and then back to the transmission (PEP BOYS sell the cooler for $40.00 and will install it for you for a small fee)
-GET the fluid PUMPED OUT every 12,000 miles
-GET the fluid PUMPED OUT and have the filter changed every 24,000 miles.

3. GEM
The generic Control Module (GEM)is the secon computer in your car. It is mounted in the dashboard behind the radio. It controls the Inside Lights, Windows, Wipers AND TRANSFER CASE (believe it or not) among other things. It is about $250 an is also very easy to change. And is aslo notorious for going bad
4. BORG-WARNER 44-05 transfer case
The transfer case is electronically controlled by the Generic Control Module (GEM). It has a INTERNAL clutch that is controlled by a solenoid (Electric Clutch). it also has 3 speed sensors mounted to it (one is the main vehicle speed sensor and is not used by the vehicle in controlling the 4wd system) two of the speed sensors are very important for 4wd operation. They are called HALL sensors and one measures front driveshaft speed the other measures rear driveshaft speed. The transfer case also has a ELECTRIC SHIFT MOTOR the is used to preform a mechanical shift of the transfer case from it's high gear range to it's low gear range.
In 2wd mode the GEM DISENGAGES the Clutch and the front axle (through the VACUUM SHIFT MOTOR).
In 4wd-AUTO the GEM engages the front axle and SLIGHTLY engages the electric clutch in the transfer case to send power to the front driveshaft (but still allow for slip so that your drivetrain isn't stressed if you are turning). It also starts reading the HALL sensors. If the rear driveshaft is spinning much faster than the front the GEM increases power to the electric clutch until the driveshafts are going close to the same speed. (NOTE THAT THERE IS NO MECHANICAL SHIFT IN THE TRANSFER CASE WHEN YOU GO FROM 2WD to 4WD-AUTO)
In 4wd-low the ELECTRIC SHIFT MOTOR shift the transfer case into low gear range (2.88:1) and fully engages the ELECTRIC CLUTCH.
This is what I learned about the transfer case:
-CHANGE THE FLUID EVERY 24,000 Miles (it only takes 1.5 quarts of mercon transmission fluid. Make sure you take the fill plugh off before you take the drain plug off in case you can't get the drain plug off you still have fluid in the transfer case)
-If you have a problem with the 4wd high mode it is probable one of the HALL sensors going bad (the rear one took me 5 minutes to change. The fron one requires removing the ELECTRIC SHIFT MOTOR to access)
-Keep the car in 2WD mode unless you need the 4wd don't waste your electric clutch on dry pavement.
-don't shift into 4wd-auto if you are going above 30mph. I have heard of people damaging the front axle if the axle doesn't engage properly
-once a month, on wet roads drive for about a mile in 4wd-auto to lubricate your front axle fully.
- TEST YOUR 4WD-LOW SOMEWHERE NEAR YOUR HOME THE FIRST TIME (You wouldn't want to find out that the shift motor got stuck in low gear in the middle of the desert would you?)
5. REAR AXLE
Most of the rear axles in '95 were the limited slip type. They take 80w90 hypoid gear oil and require 2oz of a special ford additive for the limited slip axles.
CHANGE YOUR AXLE OIL EVERY 50,000 miles
CHECK THE CONDITION OF THE OIL EVERY YEAR
MAKE SURE THE BREATHER TUBE ON THE AXLE DOESN'T GET BRITTLE AND BREAK
6. FRONT AXLE-DANA 35IFS
they are not limites slip (if you get stuck only one front wheel will spin)
the axle is supposed to tak a synthetic gear oil, But even the dealers use the same oil as the back.
CHANGE YOUR AXLE OIL EVERY 50,000 miles
CHECK THE CONDITION OF THE OIL EVERY YEAR
MAKE SURE THE BREATHER TUBE ON THE AXLE DOESN'T GET BRITTLE AND BREAK
the control module you found the tubes disconnected from is called the ELECTRONIC VACUUM CONTROL VALVE. The reason two line are going to your vacuum shift motor on the axle is to because the axle has to be DRIVEN ENGAGED and DRIVEN DISENGAGED. If the designers had only one line to DRIVE IT ENGAGED the they wouldn't have any way to disengage the axle once it was engaged.
As far as why the lines were off, I think it is stupid to pull both lines off. If you want the front axle to stay disengaged the you should leave the disengage line plugged in. your lucky the axle didn't get stuck haflway engaged and halfway disengaged. Just watch it carefully for the fisrt few days
Finally, If you are in 2wd the front shaft will still spin slowly because the transmission fluid in the transfer case still cause some small amount of energy to get to the front driveshaft.

I learned all of this because I thought my local Ford dealer was trying to rip me off. AND I WAS RIGHT.
I'm glad I could help you out. Get all your fluids changed

 

Here is some info on the 4wd clutch in the 44-05 transfer case

Have you been driving in 4wd-auto for most of the vehicle life, Maybe the clutch is just worn out. I don't suppose you have access to a hand held fluke scope-meter. you would be able to view the square wave pulse and see if it is actually correct. it would have a frequency of 33hz.

the period of the wave should be 30mSec and the On-Time should be variable, but timed as described below.

There is a lot of talk about why this PWM method is used. Most people think it it to maximize current in the coil. But I believe the more correct explanation is as follows.

If a straight DC signal is applied to a coil then after a short time period the coil would appear as a electrical short to the device supplying the DC signal, which would mean the current through the coil would be as high as possible and the DC voltage source would either be loaded down and not supplying voltage anymore. or if the DC supply was strong enough it would burn out the coil.

If a AC voltage is supplied to a coil then the coil would be producing a magnetic field (inductance) that would mimic the voltage applied but be 90degrees out of phase (the magenetic field would be pulling then pushing) the net magnetic force would be zero and the clutch would never engage

If a Pulsating DC signal (square wave) was applied, and timed so that the max on time was equal to the time constant of the coil (the Time Constant is a function of the internal resistance of the coil and the inductance of the coil and is defined as the time it takes the current to build up to 86% of it's maximum.) then the magnetic effect of the coil would be maximized without the power supply being loaded down and without burning out the coil. as the on time is reduced the magnetic effect would also be reduced thereby lowering the holding power of the clutch.

This explains why there is a diode in the circuitry . to make sure any negative voltage gets shunted to ground so the signal to the coil is really a modulated DC.

this also explains what the TOD relay is. it is really a Filed Effect Transitor (FET) amplifier that boosts the low power signal coming from the GEM.
The GEM supply a low power, variable frequency signal that is proportionate to the desired holding power of the clutch.
The TOD boosts the power of the signal so that it is srong enough to operate the clutch coil (I imagine the coil must be powerful enough to hold the clutch in. this would take a lot of juice).
the diode in the transfer case shift relay is for rectification purposes (making sure no AC gets to the clutch coil)

i think everyone who is telling us that no voltage means the clutch is engaged is incorrect. I was very confused when I first started looking at this, but as the 33hz thing kept popping up I started believing it more and more.

 

i check that thing u say and the motor and all that work on front axle i just fill it up with some lubrificant and check if i feel the air and works so could it be the transfercase? make realy mest up or broke the motor

 

ok if u say are the HALL sensors shouldnt be something like check engine on or something? flasshing or indicating the HALL sensors are broke? if not can u tell me were exacly are this sensors? so i can replace them bought