How do you use 4 wheel drive in a 2003 Chevy Tracker?

To use four wheel drive on the 2003 tracker, there is a shifter just below the manual or automatic transmission selector in the centre console. When the shifter is all the way towards the rear seats, it is in rear (two) wheel drive. Shift it up towards the dash and it will automatically go into four wheel drive high range, which means you can drive at the same speeds as in two wheel drive. You won't have to lock the hubs as they are automatically locking, and you can shift into 4wd at any speed under 60 mph as long as the whels are facing straight ahead and the shift will be immediate and unnoticed. If you are stopped, you can shift with the wheels facing anyway you like, but there will be a bit of a delay before the 4wd engages and if you are on a hill you may feel a clunk. You will see the 4wd indicator which is just above the speedometer flash once also. Try to start slowly and you won't get the clunk, but still the delay (which is about a second or so). If you are really off-road, try using the 4wd low range, by shifting the lever to the left and all the way toward the dash. This lowers the gear ratio for low crawling and is very effective for mud, deep snow, hills and other off-road obstacles. You have to be at a complete stop however to shift to 4wd low range. There won't be any delay or clunk if you are stopped. The tracker has a very good off-road ability with either low or high range and I've left jeeps and toyotas and full size trucks eating my dust off-road, due to this ability and the fact that the tracker is very light weight. You can use a one tonne come-along to help extract yourself from sticky situations if you can't afford a winch (like me). If ou are going over obstacles like rocks, or logs, always try to ride the wheels over the obstacle. The tracker has a ladder frame which is tough and most of the crucial mechanicals are tucked inside the frame, but you stand the chance of damaging the exhaust, differentials, etc. it you try to drive over the obstacle instead of letting the tires to it for you. Above all, have fun and tread lightly. Hope this helps!