I need to move my drives to the side to access a screw, but obviously can't do it with the engines running, If I turn my wheel 90 degress one way or the other with all power off will it hurt anything, note: it does not have hydraulic steering.

Never caused a problem 4 me.

shouldn't be a problem.

Just don't start the engines dry.

shouldnt, just remember that if you have hyd steering and hold at lock while mtr running it will change the wheel position

You're just pushing hydraulic fluid back and forth. It won't hurt it a bit.