Trans issues

[Mjoh1845]

Got a 2000 silverado with 5.3 just picked up. Driving it home at 55 to 70 it would shift out of overdrive under no load but get to a hill and would go into overdrive and stay there unless really hammer on her then would shift to like 3rd. At 70 under load its at about 1600 rpm and under no load it's at like 2000 ram once push on gas then shifts down to overdrive to the 1500 1600 rpm range

[asilverblazer]

It shifts out of overdrive for no reason at all?

[Mjoh1845]

It shifts out of overdrive when not under a load doing 55 and shifts into overdrive when depress gas pedal farther down to accelerate up a hill or under any load