03 Expedition 4x4 Issue

[nabil]

I have an 03 eddie bauer 5.4 with 4x4. It had a trans repair a good while now and after the repair 4hi stopped working, but 4lo and A4WD work fine. I got no contact with the previous owner who did the repairs nor the mechanic, so can't get the issue from them. There are no fault codes for the 4WD on forscan. All dash lights work fine and none are burnt. Switching to 4hi makes no sound, so I know it doesn't engage, and the light doesn't turn on. However, A4WD and 4lo both release sounds so I know they engage fine, and the light comes on for 4lo. On forscan PID reader, there is 4x4Lo and 4x4 Low range input, but no PIDs related to 4hi, which I have no idea if that's normal or not. Would appreciate anyone who can help.

 

[AWAR]

They do not make any noise between 2wd and A4wd. Only the hubs engage and the electric clutch is active as needed. 4wh is a noise shifting the transfer case and 4wlow the transfer case shifts again. I have three of these vehicles.

 

[whtbronco]

Yep, the A4WD setting simply energizes the coil which engages the clutches at whatever rate it's commanded. The minimum rate of engagement is 8%. The A4WD setting on the dash should not move the shift motor. The shift motor has only 3 positions 2WD, 4HI and 4LOW.

There's some detailed info on the transfer case in this thread from my transfer case rebuild that might help you.

Not so Good Vibrations

So I've been chasing vibrations in my '04 Expedition for quite a while, 288k miles. One I was certain was the A/C compressor, and had made plans to replace it. I'm totally lost on this, but after replacing the fuel pump my wife said the engine was running smoother and the vibration was gone...

www.expeditionforum.com