Originally Posted by totalloser

Spinning hubs uses virtually no fuel. The fuel is wasted only if you have full time 4x4. The drag is from turning the ring and pinion, thus CAD equiped trucks use virtually no more fuel than manual hub trucks with the hubs out (big myth).

Having said that, if you have non-slip rotors you probably have the old balljoint setup. If you have the old setup with the balljoints in the knuckle, the Ford knuckles will fit.

Many vehicles use some version of the CAD system (for instance ADD on Toyota trucks) to accomplish this efficiency savings by disconnecting the long side inner axleshaft. When disconnected, the short side spins the diff carrier side gear, and the spider gears walk spinning the disconnected short shaft with virtually no resistance.

Of full time axles, reverse rotation is the worst because in 2wd the road effectively pushes the "coast" side of the gear which creates more drag than the "drive" side of the gear. Dodges use standard rotation gears, so there is less drag even in a full time setup. Don't expect big jumps in efficiency from this kind of mod. Expect serviceable bearings that are more precise, stronger, longer lasting brakes, tighter steering, no death wobble (t steering versus y) and instant in and out 4x when the hubs are locked compared with slow mo CAD system.

Here's a SICK writeup of the conversion to Ford knuckles/brakes http://www.pirate4x4.com/forum/showthread.php?t=874442

Keep in mind that with this swap the diameter of the brake rotors is about the same, but the ID of the friction contact is much smaller, so the difference between the inner friction to outer friction surface is MUCH MUCH larger so you have dramatically more pad contact even though the diameter isn't really bigger. IE much better brakes.

Also, if you have 4wheel abs versus rwal you will need to address the reluctor ring/sensor issue on the hubs to make your abs system work. Dynatrac has these for their custom axles- they use a ring that presses on the inside OD of the hub and a mount for the sensor to tuck inside between the rotor and hub. Might require lathe work on the hub to machine the OD to match press fit for reluctor ring.