To answer your question , yes you can leave it either in high or low. You don't need to lock it in. Once you throw the arm one way or the other it will stay there.You can do this by hand after removing the alu. housing, make sure you put the housing back are you will have a nice oil leak. Putting the arm towards the center will move the clutch dog out and give you high. Pulling the arm to the passenger side will give you low. Either way the arm will stay where you put it. It will also stay where you put it in reverse.