so i go to the store yesterday and the truck runs fine. parked it in front of the garage and didnt think twice about it.
i go to drive it today and was going to pull out a bush in the back yard and the 4wd wont engage ?? i check all fuses inside and in engine all good
on top of that i go down the road and it acts like its in first gear ??
so i have first and reverse and when i shift back and forth it goes in w a lot of torque as if im in 4 low but im not in 4wd at all

the tranny was rebuilt 2 yrs ago and all cases serviced at that time

checked fluid and am fine there

its a 97 f250 ld 5.4

any ideas?????????

 

Sounds like the transfer case motor is stuck in the 4L position.
You will have to remove it and see if it has rotated to it's last position.
If yes, the shaft it moves has to be returned to the 2wd position and the motor tested for operation.
You may get out of the problem temporary by doing this.
There may be other issues but look at this first unless there is something else you find.
Otherwise the total operation by switch gets involved for the sequence of operations that goes on and would be confusing at this point for what condition you say you have..
Good luck.

 

if its stuck in 4l then why dont i have 4wd ??

 

The front actuator never engaged the front drive.
If your geared down, the transfer case motor operated and shifted the internal gearing.
The front drive is by engine vacuum operated actuator.
The two are seperate operations.

 

so how can i test or move it back to 2wd without tearing it apart

 

You have to work on it to see what the problem is, first.
I gave you the general operation and a place to look.

 

i looked and the motor on the t case is all rusty and i wonder if i can pop it off and test it

 

ok so i pulled the pan off and fluid was nice and clear red put it back and refilled then pulled off the little motor on the trans case and with the truck in neutral i manually turned the triangular shaft back to 2wd
then i took the motor leads to a battery and it moves fine in both directions so i ran it to the 2wd position and reinstalled it but left it unhooked electricaly
taped up both plugs to keep out dirt and insulate (figuring that the gear will physicaly hold the shaft at 2wd and without the electrical hooked up it wont move) i ran it up and down the road in all gears then into town and back ..............ran fine! shifts normal in all gears and runs fine now but i only have 2wd for now

Question ... has anyone taken voltage readings from the four prong switch ??if so what should they read
and if that switch were to go bad would it shut the system down and not allow it to shift through the ranges??
as my t case motor works im going for the switch and then what??

thanks
chris

 

Glad to see you looked at the transfer case motor and found it operated as I had suspected from your discription of how it acted.
....Now remove it again and with the plugs connected see what the motor does when you operate the switch to 4H position.
....Does it go to the first position?
....Return the switch back to 2WD and see if it returns back.
....Then try it to the 4L switch position and back again to see if the motor runs as you request by the switch.
....Then look at the contact plate for any issue with the electrical wiper connections.
....Depending on what happens you don't need to measure anything if the motor is working, the switch is good and the GEM module is working at that point unless it has corrosion from a leaking windshield and might be intermittant..

....If you find all is well, just chalk it up to being stuck unless it happens again.
....On the front actuator; It is a vacuum diaphram assembly the firewall solenoids pass engine vacuum to too either operate to engage the front drive or when the vacuum is switched to the other side of the actuator it returns it and disconnects the front drive.
....As you set inside the truck and do this, you should be able to hear it 'clunk' in and return back. The front drive actuation is done by the GEM signaling the solenoids one at a time depending on the request from the dash switch .
.. The solenoid returns a signal back to the GEM that 'in turn' lights the dash light for the mode selected.
....Note the tranfer case motor tell's the computer it's in 4L and to change the shift sked to match.
....Your best self help is understanding what is supposed to happen then detecting what part does not work correctly. Read this several times to get the info you need to know.
Good luck.

 

QUOTE=Bluegrass 7;10722661]Glad to see you looked at the transfer case motor and found it operated as I had suspected from your discription of how it acted.
....Now remove it again and with the plugs connected see what the motor does when you operate the switch to 4H position.does nothing
....Does it go to the first position?no
....Return the switch back to 2WD and see if it returns back.no
....Then try it to the 4L switch position and back again to see if the motor runs as you request by the switch.nada
....Then look at the contact plate for any issue with the electrical wiper connections.i assume this requires removal of the plastic plate on the back? will do tomorrow
....Depending on what happens you don't need to measure anything if the motor is working, the switch is good and the GEM module is working at that point unless it has corrosion from a leaking windshield and might be intermittant..

....If you find all is well, just chalk it up to being stuck unless it happens again.
....On the front actuator; It is a vacuum diaphram assembly the firewall solenoids pass engine vacuum to too either operate to engage the front drive or when the vacuum is switched to the other side of the actuator it returns it and disconnects the front drive.
....As you set inside the truck and do this, you should be able to hear it 'clunk' in and return back. The front drive actuation is done by the GEM signaling the solenoids one at a time depending on the request from the dash switch .
.. The solenoid returns a signal back to the GEM that 'in turn' lights the dash light for the mode selected.
....Note the tranfer case motor tell's the computer it's in 4L and to change the shift sked to match.
....Your best self help is understanding what is supposed to happen then detecting what part does not work correctly. Read this several times to get the info you need to know.
Good luck.[/QUOTE]

as of now its acting as if the switch is dead of the 4 conections to the switch i get about 5 volts to one of them and nothing on the other3

 

Check 30 amp fuse that feeds the transfer case motor.

 

fuse number?

 

#104 on my 02. May be a different one on yours.
Dammit, you want nme to hold your hand an give you a kiss too?
Good luck.

 

NO! but so far im gettingno power to the harness at the t case motor at all and i have power at the vacume solinoids but only one is sucking air at the actuator the pinkish line

i figure it wont switch if the motor doesnt at the t case sooooooo

i have checked every fuse in this truck under hood box and in cab panel why is there no power at the motor??

do you know what the voltage will be at the switch?? 12v? im getting 5

 

ok so update:: i have taken out both vacum relays by the battery and tested them: both are fine and i have suction on the one closest to the engine all the time
i have checked the front axel actuator and it moves freely

i have tested the transfer case motor with the 2 leads to a battery and it moves fine

i have ohmed the dash switch and it is ok

i have checked the voltage at the plug for the dash switch 5v

i have checked every fuse in the dash and the under hood box twice

i have switched the relays in the fuse boxes around numerous times and nothing else has been affected . shows me they are fine

i have checked for voltage at the plug for the t case motor and nothing

i have no clicking or any change when moving the selector switch
i have no movement on the motor when moving the selector
i have no change in vac at the front axel when moving the selector
i have no light on the dash (but they do flash at start up like normal)

WHAT HAVE I MISSED!!!!!!!!!
and above the t case motor is a sensor or something i cant see it too good but what is it and what does it do??

again 97 f250ld 5.4 auto w esof