Approximately 3 miles into my trip i smelled something burning, thought it was a tractor trailer in front of me. Then my cab filled with smoke, I pulled over on the side of the road and examined the truck. The rear sliding window on the passenger side was cherry red and smoldering. I shut off the rear defrost, the cherry went out then the window shattered. No warning or beeps. My passenger and my safety were at risk to smoke inhalation, the possibility of a wreck, or burning. Gm claims there is no recall on this. But Canada has 159k recalls on this. Vehicle has 120444 miles on it. Temperature was 45 degrees out today at time of incident