i have a 97 f150 4x4 4.6 4x4 is acting up.i put truck up on jack stands to see if 4x4 was engaging and it is for about 5 sec then stops,i thought it was the relay above glove box because you can hear it click when i put it in 4x4 the 5 sec later the relay clicks off and 4x4 is gone oh and it is stick on the floor 4x4 please help! thank you

 

Maybe the 4x4 motor is just not wanting to stay in gear and slips out?

 

You need to tell us if the front driveshaft remains turning. If it does and wheels don't turn, your problem is likely related to the vacuum system which couples the front axles.