AWD: How do I know it is working?

Hi folks, since the Bravada has the SmarTrak AWD system and there is no way to select 4L or 4H like on a Blazer or Jimmy, how do I know the system is working at all?

Is the AWD always engaged on the Bravada's or does it engage when needed? I've never felt the AWD "engage" and after seeing so many posts from others with AWD issues, I'm curious how SmarTrak works.

Your Smartrak is electronically controlled and off most of the time. There are 2 sensors that watch for a difference in rotation speed between the front wheels and back wheels. When the rear wheels are rotating faster than the fronts, the sensors signal ends up with a signal to the encoder motor to engage the front drive.

Sometimes backing up while doing alot of steering will also activate the Smartrak, making some feel awkward.
Since you're doing some 90k maintenance, a transfer case fluid change to the Autotrac II blue fluid, available at your local GM dealer, would be a very good idea before the old stuff starts gumming up the critical parts. Pulling the 4WD fuse will keep the Smartrak out of service until you think you'll need it.

The easiest way to test your AWD is in some wet grass, stomp the accelerator pedal for a half second while in Drive then let up, put the shifter in Park, get out and see if you spun up some grass on 2 rear wheels & at least 1 front.