1998 Other GMC Models V8 Four Wheel Drive Automatic 120000 miles
1998 GMC K-1500 Z-71, The 4WD is engaged all the time even when manual shifter is in 2WD. When you accelerate from a stop, it makes a grinding/roaring noise. It feels like a motor mount is broke but they are fine. When it makes this noise the 4WD drive indicator light comes on, when noise stops, light goes off. While drving, it IS still iin 4WD. I have replaced drive axles, actuator, and u-joints. Can any one help with my problem, I am running out patience and its hunting season. HELP!