4wd prob on 1500

[mattd]

i have had my switch replaced for the typical 4WD problem, which was replaced when i first got the truck used. since we ahve snow i have been using auto 4WD........but it seems like when i'm in auto 4WD its really in constant 4WD. my gas milage drops like crazy, i dont feel a slip - then engage like i think there should be, and when i turn hard out of parking spots i get that 4WD drag. so it really seems like my auto 4WD is always engaged. could the new switch have been plugged in wrong? or is there something else thats common with these switchs?

[TonyMazz]

In the Auto 4WD mode, the transfer case shift control module monitors rear wheel slip speed, based on the inputs from both the front and rear propshaft speed sensors. When the vehicle experiences a rear wheel slip condition, the transfer case shift control module sends a pulse width modulated (PWM) signal to an electronic motor, which is the transfer case encoder motor.

 

This motor rotates the transfer case control actuator lever shaft, applying a clutch pack. This clutch pack is designed to deliver a variable amount of torque, normally delivered to the rear wheels, and transfers it to the front wheels. Torque is ramped up to the front wheels until the front propshaft speed sensor matches that of the rear propshaft speed sensor. Torque is ramped down to the front wheels. The process would repeat if rear wheel slip is detected again.

 

Might have a bad control module......???