I have a 96 F150 Eddie Bauer 4x4 with on the fly 4x4 shift (push button) My gas mileage seems to be low at 10-11 local and 14 hwy. Could I expect an improvement if I went with self locking hubs? An would there be any conflict with the push button design of the truck?

 

Your '96 F-150 should already have automatic locking hubs. Changing them to manual hubs would have no effect on your gas milage or the electronic shift feature (aside from having to get out of the truck to lock in your hubs.) I had a '95 F-150 4x4 with the 5.0L auto, and 14mpg was the best I ever got too.

However, some people prefer the manual hubs since they are more durable than the automatic hubs under heavy use. The '97's did away with locking hubs altogether and engage/disengage in the differential

 

Wow,
I get 14 mpg local, 17-18 highway on my 94 f150 ext cab 4x4 with the 5.8L. What gears do you have, I have 3.55's