When I first startup the truck the fan engages and really blows some air,(least it sounds like it does) then in a mile or two the loud air sound goes away so I figure that at that point it disengages. However, lately it seems to take forever to, "disengage". Yesterday in stop-and-go driving it was still engaged after a 10 mile trip to Lowe's. It was about 74 degrees and the A/C was off. I don't believe it's normal for the fan to stay engaged for so long. Is it?

 

Sometimes mine stays on longer than other times, but not for 10 minutes. Maybe a few blocks when driven right after start up or 2min at idle.
Rotate your fan when engine is NOT running. It should not free wheel or have any roughness to it. it should rotate relatively smoothly and have some resistance.
I think your fan is fine, but check it to be sure.

 

New,

Is the temp in the normal range?

 

The temp. guage is at the the same place . This morning I went for another ride and same problem. After I shut the engine off I spun the fan blade...I could rotate it with my little finger.