No 4x4 Low

[BobWiersema]

I searched around and I cant find much on my year.
98 Ex xlt 4.0L sohc all stock.

I went to use 4x4 low today and nothing.
I was in 4x4 high so I backed out of the drive, put it in Neutral, flipped the switch to 4x4 low and nothing, so I put it in Reverse backed up, went forward, no low just the 4x4 High light lit on the dash.
First time I ever had a problem with this, what should I check?
Any help would be great.
Thanks,
Bob

 

[amace013]

i have the same problem, but mines an 01 sport!

 

[Xplorer82]

you have to have the truck in neutral and foot on the brake before it will go into 4Low.

 

[scucci]

Shift motor comes to mind:
http://www.explorerforum.com/forums/showthread.php?t=123542

 

[BobWiersema]

Shift motor comes to mind:
http://www.explorerforum.com/forums/showthread.php?t=123542

I thought that was mainly 1st gen. I didn't see anything relating to 2nd gen Ex's. and a shift motor. My trans and transfer case looks nothing like that. I'll have to check on what trans it is but something like 4r55 rings a bell.

If the shift motor was bad would I still have 4x4 High and Auto? Because thats working fine.

 

[dogfriend]

I thought that was mainly 1st gen. I didn't see anything relating to 2nd gen Ex's. and a shift motor. My trans and transfer case looks nothing like that. I'll have to check on what trans it is but something like 4r55 rings a bell.

If the shift motor was bad would I still have 4x4 High and Auto? Because thats working fine.

A 98 w/ 4.0 will have a 5R55E trans.

4wd Auto and 4wd High are both controlled by the GEM sending a signal to the TOD relay which in turn sends current down the infamous brown wire to engage the electromagnetic clutch to send torque to the front driveshaft.

The switch between High Range and Low Range is also controlled by the GEM which reads the resistance from the switch on the dash to determine 4Auto, 4High or 4Low. If you select 4 Low, the GEM sends a signal to the Shift Control Relay which then sends a larger current to the shift motor to turn the range selector. The shift motor also has a set of plates built into it which gives the GEM feedback to determine the position of the shift motor.

If it is not shifting into Low range, I would check the shift relay which is located near the GEM. There is more discussion and pics in this post (and thread):

http://www.explorerforum.com/forums/showpost.php?p=2352767&postcount=71

The complete thread: http://www.explorerforum.com/forums/showthread.php?t=262252

 

[scucci]

I thought that was mainly 1st gen. I didn't see anything relating to 2nd gen Ex's. and a shift motor. My trans and transfer case looks nothing like that. I'll have to check on what trans it is but something like 4r55 rings a bell.

If the shift motor was bad would I still have 4x4 High and Auto? Because thats working fine.

I just repaired my shift motor on my 98 sport this morning. It first got stuck in low and then got stuck in neutral, when my son tapped on it I got back into high and wouldn't go into low. Cleaned up the commutator and brushes and cleaned and lubed the gears and freed up the almost impossible to turn encoder(crc silicone spray lube on the shaft) and it works great now.
Auto and High only engage the clutch, they don't shift anything inside the case. They are purely electrical. Auto sends a pwm current to the clutch to cause partial clutch engagement. Two speed sensors in the case sense the difference in shaft speeds to apply more lock up to the clutch when needed. High sends a 100% pwm to the clutch to lock it on full time. The shift motor has one function - to shift into and out of low range.
The motor end encoder is similar to the early style, but you can't get to the sealed encoder contacts. The removal is similar to that link, except you need to remove the two magnetic sensors from the case - 1 bolt each. The brown wire must be removed. Pull the red lock out and then use a jewelers screwdriver to gently move the plastic hook while pulling the wire. Scribe witness marks on all removable parts, including the encoder cover held on by torx screws. It has slots for adjustment and you don't want to get it back on out of adjustment.

 

[BobWiersema]

Scucci and Dogfriend,

Thanks for the great info. You guys cleared that up for me.
I cant tell you how thrilled I am about that relay location. Can I just once have a problem that does not involve taking the dash apart?

Should I start at the relay? or can I check for 12v somewhere on the shift motor? I think checking the connector at the transfer case would be easier if possible.

 

[scucci]

The yellow and orange wires going into the motor case are the power wires. When shifting into or out of low they will have 12 volts across them until the encoder contacts signal the gem that the motor has completed the shift. If nothing there, then the transfer case shift relay module near the radio and gem needs to be checked.

 

[dogfriend]

You can check for power at the transfer case connector. Here is the pinout for that connector from the 99 manual. It should be the same for 98.

 

[BobWiersema]

The yellow and orange wires going into the motor case are the power wires. When shifting into or out of low they will have 12 volts across them until the encoder contacts signal the gem that the motor has completed the shift. If nothing there, then the transfer case shift relay module near the radio and gem needs to be checked.

Thanks,
I hope to have time to check it tomorrow, but first I need to put a fuel pump in my sons car. So if I put it in low, pull it in the garage, jack it up and turn on the ignition I should have 12v at Yel and Org if not can I jump out the relay to see if he is the problem or is it more then just a simple relay?

 

[dogfriend]

Here are the schematics

 

[scucci]

Here is a good link to a pdf with t-shooting and locations of relays, etc.
http://www.rsgear.com/articles/2001_05.pdf

 

[BobWiersema]

You guys have armed me with everything I need to troubleshoot this tomorrow. Thanks again.

Looks like the dash switch cant be jumped because it uses variable resistance but something I think I should be checking.

 

[BobWiersema]

Dogfriend,
Am I following that schematic correctly? In the center schematic it shows a Electric Shift Control Module, is that this picture?

 

[dogfriend]

Dogfriend,
Am I following that schematic correctly? In the center schematic it shows a Electric Shift Control Module, is that this picture?

Yes, they call it the Electric Shift Control Module, but in reality, it is two relays (one to shift from L to H, the other to shift H to L) and a diode that prevents the current from the brown wire from feeding back into the circuit.

 

[stephan325i]

You can check for power at the transfer case connector. Here is the pinout for that connector from the 99 manual. It should be the same for 98.

Sorry to rob this thread, but i hoped you (dogfriend) could help me. I need a diagram with a list like this for my 95 ford explorer, but the problem is that the one i need is a little more complicated......... i need a list of what wires go to what for this plug.....

its located here

again sorry for stealing this thread for a post or two.....

 

[dogfriend]

Sorry to rob this thread, but i hoped you (dogfriend) could help me. I need a diagram with a list like this for my 95 ford explorer, but the problem is that the one i need is a little more complicated......... i need a list of what wires go to what for this plug.....

I understand what you want, but unfortunately, I do not have it. Because that is an inline connector (connects one harness to another harness) Ford doesn't give you locations where the wires are going. I have the same diagram as you posted in my 97 manual, but it only lists the circuit numbers and color codes, not what the wire does.

I guessed that based upon location the wires were somehow related to the instrument panel, and I was able to find out that 6 of the wires go to the Anti Theft module. So, I found 6 wires for you, and 2 positions don't have wires, so only 76 more to go. :

 

[stephan325i]

ha, thanks for the help anyways, hopefully i can eliminate these six wires now.

 

[BobWiersema]

Sorry to rob this thread, but i hoped you (dogfriend) could help me.

You are welcome to hijack this thread. My problem is the shift motor and its still snowing. So Ill get to that when I get to that.

Peace Out,
Bob