I have a 2001 Ford Explorer Sport. The 4 electronic wheel drive system does not stay engaged all the time. It seems like when the vehicle is cold it will go in without any problem, but once it warms up it seems to go in and out of 4. Sometimes it will not go in at all. You can hear clicking under the dash when this is taking place. Any ideas of what to try?

Thanks

 

The clicking is the relay(s) to activate the shift solenoid. Problem is probably your shiftsolenoid. They've gotten better over the years, but they still get crudded up inside. It's about the size of a wiper motor and bolted to the back side of the T-case. Unplug electrical connection and remove from the T-Case with security torx. Clean up and re-install.