Cant remove front rotor on my 2009 gmc 4 wheel drive canyon.

SOURCE: 1994 GMC Suburban front hub / bearing removal

Knock the wheel studs through the assy.

SOURCE: 1990 GMC Sierra 4x4 1500

the connections near the front axle that activate the motor to engage the system aren't melted? That's a comon problem for that body style. If there good, sounds like it could be that motor itself. To figure out if it's you motor or transfercase, jack up the rear end, have a friend inside shift into 4 wheel drive, or try to, and put it in gear and apply some gas. If the front driveshaft is turning then it's something with the front end. If not, farther back in the system.

SOURCE: Front drive, 4 Wheel drive won't engage

Check the switch on the transfercase remove the vacume lines if there is oil in them the switch has to be replaced and the lines should be cleaned out you should also check under the battery tray to make sure the boot is not ripped that controls the leaver to engage the front axel

SOURCE: how to change front rotor on 4wd 2004 canyon

The rotors bolt in from behind the hub and bearing assembly, very bad design! GM states you have to remove the steering knuckle, the bolts from the hub assembly, then the ABS sensor ring, then the rotor bolts and it will come off. To re-assemble, install the knuckle in the truck, bolt the rotor to the hub assembly, then the ABS part, then install on knuckle.

A long, drawn out procedure, takes 5 hours to change both rotors if you know what you're doing. Get a manual if you're going to try and tackle this job, it's a PITA.

SOURCE: Remove front Brake Rotor

Try opening up the caliper with a flat screwdriver thru the opening in the middle of the housing.pry on the rotor and pull towards you to push the rotor back.That should loosen it up enough for you to get it of the rotor.If that dont work you probably got a stuck caliper and have to release the brake line and do the procedure again. GOOD LUCK