'97 Chevy Chyenne will grind 2H,2L,4L unless engine is off

[klover]

It has a 6.5 with and automatic. I rarely need 4x4, but need to stop the engine inorder to shift in or out of the selection. It sounds as if gears are grinding, and needs a few seconds even after the engine has been turned off.

 

[bison]

You need to shift fast from 2H to 4H in one smooth motion,going from 4H to 4L you should shift the tranny in neutral or stop before you shift the T-case