I have a 2012 F150 with 5.0l, ESOF. Have been having problems with 4WD engaging. The check 4x4 light comes on but most of time will engage into 4H or 4Lo. Sometimes it won't. I have replaced the transfer case motor, vacuum solenoid, vacuum lines, and selector switch on the dash. I have put a vacuum pump on the IWE's and they hold vacuum. When I get the check 4x4 light but still engages the vacuum from solenoid is off. When get light but not engaging still has vacuum coming from switch. I'm not sure if there is an electrical problem of if the IWE's could be causing this. Sometimes I can hear a loud clank under the truck when it shifts into 4WD, most times smooth as butter. Would love any suggestions. Thanks

 

[QUOTE=bnyberg;5270204]I have a 2012 F150 with 5.0l, ESOF. Have been having problems with 4WD engaging. The check 4x4 light comes on but most of time will engage into 4H or 4Lo. Sometimes it won't. I have replaced the transfer case motor, vacuum solenoid, vacuum lines, and selector switch on the dash. I have put a vacuum pump on the IWE's and they hold vacuum. When I get the check 4x4 light but still engages the vacuum from solenoid is off. When get light but not engaging still has vacuum coming from switch. I'm not sure if there is an electrical problem of if the IWE's could be causing this. UPDATE: I have now replaced the IWE's with Dormans IWE. The one that does away with the vacuum. I still get the CHECK 4X4 light. It engages in 4WD most of the time but sometimes it won't Out of ideas, Please any help would be great.

 

Sorry I can't help. But, the clank I hear on my 02 is when 4Lo engages. There is no noise when 4Hi engages. I don't think many members know much about 4WD on this site.