I heard a loud rumble from the rear end and had a diagnostic which stated there is a problem with the rear differential and its leaking oil. Does this mean it needs to be replaced and how costly is this type of repair?
Rear Differential repair on 1998 Ford Expedition
the noise is the problem. that could be a bearing or ring and pinion. yes, it is costly. overhauls are around 900-1300 depending on needed parts.