I believe it's the rear differential vent hose.
It may be your differential or your whole rear end or it could just be a worn out gasket.
On a 2004 Ford Expedition , 4x4 : The front differential has a tube ( hose ) coming off the top of the differential ( the biggest part of the case where the gears are )
It is a vent for the rear diff. Attach it high up anywhere so water can't get into it.
That is the axle vent hose. It ties off to the body above the axle.
That hose is the differential vent hose. It is held onto the chassis up under the motor by a small clip. The hose does not attach to anything other than the differential.
Fluid level too high, water in fluid, axle overheating.
rear differential got lube? rear wheel bearings?
As far as I know that is a vent hose and it just goes in an upward direction somewhere where it won't get damaged
If its coming from the rear differential, add some additive, available from chevy.
All Ford Rangers have a rear differential , and if they are 4X4 equipped , a front differential also
The rear differential pertains to a motor vehicle and means the differential that is situated in the final drive of the transmission assembly, found in rear-wheel drive vehicles.