Just bought '94 f150 xlt with 5.0 and auto trans. Used 4wd for first time the other day and after going back to 2hi my speedometer and odometer no longer work and my od light is flashing.

I changed the speed sensor which wasn't the problem and noticed that the fluid in the rear axle housing smelled burnt (I assume burnt because it stank).

I had o'reillys read the engine codes but all they got was speed sensor and knock sensor codes for not giving a signal. check engine light hasn't come on.

The truck starts and drives fine, I can still switch to 4wd and back and drive like normal, but I don't want to screw anything up driving with an unresolved issue.

 

its not moveing at all corect check to make sure the gear didnt strip not sure if the 94 uses direct cable or not if it uses electronic then have no clue but if its mech then its way eisier to fix just get under the truck and take the one or 2 bolts that hold it in place and see if the gear is sreaded if so replace and be done with it if not then check from the spedo if its turning the cable but not turning the speodmeter etc

Tom

 

First check all the fuses, then check the wiring harness that goes to the speed sensor. These electrical problems can be a pain to sort out.