I have a 2005 KR that the 4wd doesn't lock in the front wheels. I haven't seen my exact problem as I have been searching it. When I turn the switch
the dash lights both in high and low 4wd. I hear the transfer motor engage in both hi and low. No ratcheting noises from the wheels. I have replaced the solenoid. And still nothing. Checked fuses And they are OK. Thanks in advance for your advice.
mlm1013

 

Did you read through this yet? Could be a vacuum problem...

https://www.ford-trucks.com/forums/8...then-some.html

 

Perhaps a bad solenoid, not releasing vacuum?

 

Hey there, I am having the same issue with a 2006 F-150. Here is the test that we performed on the mechanics, not the vacuum, of the system:

We put all 4 corners in the air with jackstands. With the engine off, checked to see if the front hubs were engaged with the wheels by turning the tires. The wheels turned, but the half-shafts didn't. Bad sign. With engine running, in 2WD, wheels still turn freely, half-shafts don't. Turn on the 4WD inside, dash lights to 4H, and in Drive, the front wheels don't turn, but the half-shafts do. I suspect both IWEs are shot, and are stuck in the "OFF" position, the vacuum has no effect on either.

We haven't checked the vacuum system yet, still waiting for the snow to melt off and the slab to dry.

Does anybody here know what needs to be done to replace the IWE assemblies? Looks to me like the half-shafts have to be pushed out of the steering knuckle to get at the IWE.