97 Expedition 4WD not working
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97 Expedition 4WD not working
The 4WD on my Expedition was not working......I could hear the transfer case motor go into 4LO and the lights on my dash appeared to work just fine. Everything appeared to work OK except there was no 4WD.
I searched through the Forum and found a case identical to mine which pointed to the vacuum diaphragm located on the front axle which is used to engage the axle for 4WD. I removed the protective plastic cover from the diaphragm and used a mirror on the floor to watch its operation while engaging 4WD.....it barely moved. I got underneath and moved the lever with some channel locks to engage the axle and took it out for a spin and found I had 4WD. I then checked the vacuum lines for leaks especially behind the battery at the firewall and then removed the vacuum lines from the diaphragm to find there was vacuum.
I tried to move the axle lever by hand with the vacuum lines disconnected and found it could not be done. I sprayed some WD40 where the lever shaft goes into the axle to free it up. The WD40 worked so I even put a couple drops of 3 in 1 oil for extended lubrication. The lever was now very easy to move back and forth with my hand even though it only moves about 3/8". The 4WD system now works just fine.
I have heard that the diaphragm on the axle is rarely replaced and for the most part does not go bad.....good thing because it costs $100 bucks from the Dealer. The problem is usually either the vacuum lines to the diaphragm or lubrication is needed where the lever goes into the axle.
Thanks to the people of the Forum.
I searched through the Forum and found a case identical to mine which pointed to the vacuum diaphragm located on the front axle which is used to engage the axle for 4WD. I removed the protective plastic cover from the diaphragm and used a mirror on the floor to watch its operation while engaging 4WD.....it barely moved. I got underneath and moved the lever with some channel locks to engage the axle and took it out for a spin and found I had 4WD. I then checked the vacuum lines for leaks especially behind the battery at the firewall and then removed the vacuum lines from the diaphragm to find there was vacuum.
I tried to move the axle lever by hand with the vacuum lines disconnected and found it could not be done. I sprayed some WD40 where the lever shaft goes into the axle to free it up. The WD40 worked so I even put a couple drops of 3 in 1 oil for extended lubrication. The lever was now very easy to move back and forth with my hand even though it only moves about 3/8". The 4WD system now works just fine.
I have heard that the diaphragm on the axle is rarely replaced and for the most part does not go bad.....good thing because it costs $100 bucks from the Dealer. The problem is usually either the vacuum lines to the diaphragm or lubrication is needed where the lever goes into the axle.
Thanks to the people of the Forum.
