I recently bought my 98 expedition and have had no issues with the trans. Went to take my kids dirtbike riding and in order to get back out of the place we ride, I had to shift into 4wd low (It started raining and I did not want to get stuck. When I test drove the truck, it shifted into and out of 4wd with no issues. Since where we ride is only a few miles from my home, I went straight home with it. I checked with a freind, who knows slightly more than I do and he suggested I change the shift motor as he has heard they are notorious for going out. I changed it tonight and when doing so, the shaft would not line up. I started the truck, put it in neutral (chocked the wheels of course) and took some pliers and checked to see if I could manually select 2wd. I turned easily, so I then mounted the motor. I was very careful to make certain that all of the wires that needed to be removed form the old harness and into the new one were in the exact locations they came from. I took it for a test drive and it seems to be driving in 2wd just fine. However, the indicator in the instrument cluster still shows 4wd low, and the overdrive light on the shifter is blinking "off". I do not want to drive it for fear of making something that should be simple into something major. After doing some reading, I feel my shift solenoid or my switch may be bad. How can I test these components? I bought a repair manual, but there are no readings that I can find.

 

probably gotta be reset the computer from plugging different one in. u shouldve left it in 4wd low and gun it a few times then move switch slowly back.....
i had a weird prob like that....was switch. but this year...i had put it in 4wd low and it wouldnt switch back...i was in park. i put in drive....drive it like 50 yds....stopped and switched it back to 2wd in park. never did it again.....all last winter i used 4wd high with no probs..

old truck.....i got same yr