My wife has a 2003 expedition 4x4 with 5.4 V8. I was changing the oil this afternoon and noticed gear lube leaking out from the passenger side axle housing.(not sure if thats what its called.) Any way I assume a seal is bad. After oil change I pull diff plug and fluid is low but hey at least its there I top it off and head out to do a couple of things and stop by my mechanics. He gets underneath the truck and asks me to roll the truck in neutral. He says the 4x4 is still engaged and has worn out the seal. I ask what makes him say that and he proceeds to tell me that the front axle is spinning when rolled thus in 4x4. I say I don't think so, I think the transfer case is not engaged and does not feel like driving in 4x4. He says there are vacuum lines going to front hubs and they engage/disengage the axle and are common to fail. Anyway I tell him thanks and leave not convinced that is the problem. Can anyone tell me what they think about the problem I have. By the way on my way home stopped by a dirt road and put it in 4x4 Hi and Lo and was definetly in 4x4 and disengaged a little slow but did it fine.(probably from lack of use) My mechanic is a good guy and I don't believe he is trying to rip me off but I do believe he is confused about this 4x4 system, but I've been wrong before. Sorry for the long post but ideas would be appreciated.

 

i deff agree it is not in 4x4 the seals can go out true but the vacum lines are not engaged and i thnk the best thing to do would take the tire off and see the damage and go from there. is the other side doing the sam or just the one side?

 

It is only on passenger side with the leak, but he said the axle shafts are not supposed to turn while in 2x4 and I think he is wrong. What do ya'll think?

 

If it works the same as a jeep 4x4 system works then both axle will turn when not in 4 wheel drive. The way the jeep system works it when you put the transfer case in 4 wheel drive it sends the signal to the vacuum module on the front axle to actuate a fork to move a slip collar which couples the axle shaft.

Does the Expedition have manual locking hubs? If it does then the axles should not turn.

 

You have a front axle seal out.

If you can feel it go into 4x4 then that indicates its not in 4x4 at the other times.

Put it up on jack stands put it in 4x4....You will be able to tell for sure if it is working properly.