I have a 98 Tahoe . The 4 low function was not working. So I read you need it to be moving about 1mph and to be in neutral before hitting the 4 low switch . I did that and still nothing. Now I don’t have any trans at all ! It won’t go into park or any gears even reverse . I can here the front 4x4 actuator work when I press the switch but still nothing. Do any of you have any ideas of what I could check ? Thanks for any input.