I am having issues with my putting my truck into 4hi and 4low. on 2004 Chevrolet Silverado 1500

I have a 2004 chevy Silverado z71 with 116,000 mile on it. For some reason I am unable to put my truck into 4hi or 4low, but able to put my truck into auto and 2wd.

by in Jessup, PA on January 02, 2013
1 answer
ANSWER by on January 02, 2013
SCAN 4X4 MODULE FOR CODES AND POST SO WE CAN ADV POSS BAD SWITCH OR ACTUATOR