I have a 2005 FX4 it only has 37000km and I am having a problem with the 4x4. When the truck is in 4wheel hi or low there is a hum and if I turn hard to the left or right (at slow speed) the truck will stop. Even under acceleration the truck will not move? Any thoughts. The truck will turn without a problem when it is in 2wheel drive. THX

 

Not sure what the hum might be, but if you are engaging the 4x4 on dry pavement, then it will not move with the wheels turned all the way. This is due to axle bind. The CV axle will bind and actually needs to "flip" when turned all the way due to the excessive torque put on them at extreme angles. When off highway, you don't notice it due to the wheels will "slip" and allow the axle to unbind. If you read the owners manual, it will state not to run 4x4 on dry ground. On the other hand, if you had an issue with say different gear ratios between axles, the truck would not move at all when in
4x4.

 

Thank you for the reply bigbronc. When I first noticed the problem it was freezing rain so it might have been wet pavement. So maybe all it was doing was binding, because we had a snow storm last week and I tried it in a tight circle and it seemed to be working.

Thanks again
Mike

 

I have an 05 fx4, and my 4x4 wont engage. The vacuum switch on the firewall went out while I was driving and the grinder full of ice sound started. I replaced the switch and it stopped. But now it wont engage into 4h or 4l. When I try to engage it the grinding starts again. Im wondering if the hubs were damaged when the switch went out, or if it could be something little. Im planning to get it fixed soon and just wanting to know if it will be a small fortune or if i could fix it myself. Any advice is much appreciated.thanks.