good friday to everyone. 2001 xlt expedition, i have had this truck for a few months with some minor problems. i took it in for a brake check and when they pulled the rear wheels off, we noticed oil from the the rear differential on the rotor guard of the brake, right side only. tehy want to replace this seal and turn the rotors and replace the pads. will this fix the squealing brake problem? thanks,

This is fuel economy related? :)

The seal should definately be replaced. If the pads got gear oil on them, they must be replaced. If you replace pads without turning/replacing rotors, they will most likely squeal more, and wear out faster.