I have a 200 silverado 1500 with a 4l60e tranny, all of a sudden it stopped shifting out of second gear. First and second work fine, so does reverse, but goes into limp mode after second. I have removed the pan and inspected it for any shavings, none found. I have also pulled and tested the A &B solenoids, which are both reading 22 ohms. Where should I look next?