WHERE ARE THE WHEEL SENSORS LOCATED ON MY 2008 GMC SIERRE 1500 THANKS

Check rockauto.com for pictures of what they look like. They are listed under "Brake/wheel hub"

You might think that a four-wheel, anti-lock brake system would have a speed sensor for each wheel -- but, on the 2008 GMC Sierra, this isn't the case. Technically, there are only two ABS sensors – one for each front wheel. The vehicle speed sensor installed in the tail section of the transmission acts as the ABS sensor for the rear axle.

Is that true for a 2004? I want to get a stronger axle but don't want to lose ABS in the rear. Thanks.