99 Ranger 4wd stopped working

[Tom_G]

Aloha all!

I haven't had the need to use 4WD in a couple of years. Right now, we're in the middle of tropical storm Olivia. Tons of rain, wind, lots of standing water on the streets. Great time to switch on 4W high, right?

I locked the hubs (yes, I replaced the hubs with manual lockers years ago.) Switched the switch to 4WD High. Nothing happened. No lights came on. I thought it might just need a minute, so went ahead and started driving. Then both the 4WD HIGH and 4WD LOW indicators flashed at me about 5-6 times, and went dark. I played with the switch a couple of times, putting it back to 2WD, and even taking advantage of a stoplight to try getting into 4WD low. Nothing I did made any difference, so I finally just left the switch in 2WD. For the rest of the drive, though, both warning indicators would periodically flash a few times.

Thoughts?

Mahalo!
Tom G

 

[Dirtman]

Most likely the transfer selector motor is frozen up from not being used.

 

[fastpakr]

Yep, sounds like it got stuck between positions so the GEM isn't getting feedback from the touch drive sensors to know what position it's in now. I'd pull the motor and get everything moving smoothly.

 

[RonD]

Welcome to TRS

+1 to Dirtman's post, tap on the shift motor with a hammer, that might free up the motors brushes.

When an electric motor sits for long periods the Brushes that pass voltage to the Rotor can stick, so when you try to use the motor it doesn't get 12volts or ground.

Flashing 4WD lights means the 4x4 Controller is working, but when it sent 12volts and Ground to the shift motor it didn't move, or stopped moving.

Inside the shift motor is a Contact Wheel, the Controller monitors the contacts, so it always "knows" what position transfer case is in, 2WD, 4Hi or 4Low
When Controller sends voltage to the motor it will see contacts change, if it doesn't then it Flashes 4WD lights to indicate the problem

Pictures here of shift motor: https://www.explorerforum.com/forums/index.php?threads/how-to-rebuild-4x4-shift-motor.123542/

Best practice is to shift into 4hi and 4low then back to 2WD once a month, just sitting in the driveway, don't have to lock the hubs or drive, you are just cleaning the brushes and rotor for future use

 

[Tom_G]

Thanks for the suggestions and pointers! Wouldn't you know it, when I got in the truck to go home after work, the switch worked. I'll make a point of engaging both 4WD high and 4WD low daily for a little while to try and get the vapors out of that transfer motor, then make sure to do that every couple of weeks from now on.

Thanks again!