auto 4x4 engaging on dry pavement under acceleration

[powrck32]

I have a question for some of you guys out there.
I have a 98 explorer 4dr withthe auto 4x4 (torque on demand) system on it. Everytime I go to take off from a stoplight It feels like the front end is engaging. I have replaced both front and rear axle speed sensors, cleaning the 4x4 motor but to no avail. I have also tried resetting the computer. I dont know if this condition is normal or not, but it sure is a lot of noise for this to be a normal condition

Also 4hi locks in just fine and 4 lo locks in after a few seconds, but one 4 lo is locked in, you have to turn the truck off and restart it in auto to get it out of 4 lo. I sure would appreciate some help on this. Most repair shops just scream that the xfer case is bad and go on. Just wondering what you guys thought
Thanks

 

[Robert]

Your first problem could probably be fixed by updating the programming in your GEM. The second problem (assuming you are putting it in N with your foot on the brake when you try and take it out of Low) sounds like a faulty transfer case shift solenoid. When you turn the key off and restart it, it forces the solenoid to re-home itself if the switch is in Auto. Here is the text from a TSB that sounds similar to your problem, however it was issued for Explorers built through 4/97

Transfer Case - Shudder/Binding In Tight Turns
Article No.
97-21-15

10/13/97

^ SHUDDER OR BINDING SENSATION - IN TIGHT
TURNS WHILE VEHICLE IS IN 4X4 AUTO MODE -
VEHICLES BUILT THROUGH APRIL 1997

^ TRANSFER CASE - SHUDDER/BINDING SENSATION
IN TIGHT TURNS WHILE VEHICLE IS IN 4X4 AUTO
MODE - VEHICLES BUILT THROUGH APRIL 1997

LIGHT TRUCK:
1995-97 EXPLORER

ISSUE:
A shudder or binding sensation in tight turns while in 4X4 Auto Mode may be experienced on some vehicles. The shudder is due to a high torque output from the clutch in some transfer cases.

ACTION:
Recalibrate the existing Generic Electronic Module (GEM) if the GEM is identified with engineering part number F77B-14B205-BB. The revised calibration commands a lower torque which allows the transfer case clutch to engage smoother so shudder or binding should not result. Refer to the following Service Procedure for details.

SERVICE PROCEDURE

Using Service Bay Diagnostic System (SBDS) machine, use the latest software release to recalibrate the GEM to command a lower minimum torque level from the transfer case. Follow the instructions below:

1. Select "Body, Chassis, Electrical" from the SBDS Main Menu.

2. Enter the Vehicle Identification Number (VIN) of the vehicle being serviced and continue to the "Body, Chassis, Electrical" menu.

3. Select "Module Reprogramming" under the "Category" scroll box, and "Module Reprogramming" under the "Tool" scroll box.

4. Follow all on-screen instructions, continue to "Module Reprogramming Procedure" screen and select "GEM Module, Shudder in 4X4 Auto Fix, 4X4 Auto Fix."

5. Again, continue and follow all on-screen instructions until the GEM module has been reprogrammed.

6. A copy of the log can now be printed to document what has been done to the vehicle.


If the new calibration does not satisfactorily resolve the concern, refer to TSB 97-3-14 for additional corrective actions.

OTHER APPLICABLE ARTICLES: 97-3-14

WARRANTY STATUS: Eligible Under The Provisions Of Bumper To Bumper Warranty Coverage

OPERATION DESCRIPTION TIME

972115A Reprogram Generic 0.4 Hr.
Electronic Module (GEM)
Using Service Bay
Diagnostic System (SBDS)

DEALER CODING
CONDITION
BASIC PART NO. CODE
7A195 42

OASIS CODES: 303000, 508000, 703000, 703200