2010 FX4 | 8.8 | Castrol Syntec 75W-90 | 67,000 Mi

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Staff member
May 14, 2007
Indianapolis, IN
Originally Posted By: Jim Allen
FYI to all, Ford uses devices call Integrated Wheel Ends (IWE) that are essentially vacuum operated hub locks that are internal to the hub. Nothing in the diff turns when they are disengaged.
OK - I'm familiar with that concept. We rebuilt the front drive hubs of my neighbor's 2005 6.0L F350 this past winter; had to replace the inboard large seals behind the unit bearings that affect that vacuum chamber. Interesting system; uses the vacuum pump to shift the hub collars, as well as run the HVAC box. Works great when it works; it's a bit of a PITA when you're trying to find where the leak is at. If this 2010 FX4 is similar, then I can see where "normal" low 4x4 use would leave the front ring gear idle nearly all the time. Completely opposite of my GM; wherever the rear diff goes, the front diff has already been, turning all the time, just a few yards ahead of the rear.
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