possible bushing in you suspension, swaybars, shock bushings, bad shocks. if it happens at slow speeds, get another person to listen for it as you drive and try to focus on the area. should be able to locate it if that's the case. or try pushing down on the bumpers to simulate bumps and listen for the sound.
If it is like mine--the squeaking will eventually occur all of the time while driving. I had to change the universal joints on the drive shaft at 70,000 miles. GM should be ashamed, with gas prices as high as they are, every mile on this truck has been driven gently.
Check your universal joints!
It is important to know the weight of a vehicle while driving it. A 2007 Chevy Avalanche has a gross vehicle weight of 5,742 pounds.
40 on idle up to 60 while on the move.
If it squeaks while it moves but not while it's at idle then the squeaks are body or suspension noise.
The drive belt may be slipping or going bad.
To put a Chevy Trailblazer into four wheel driver, locate the four wheel drive component below the instrument panel. While the car is in drive, move the knob into the desired four-wheel drive position.
check refrigerant level. if is ok,, replace the low presion swicht locate on acumulator.
possible have a bad master cylinder
You most likely have a leaking heater core, check you coolant level first while the truck is cool........
Bad wheel bearing? Brake pads worn? Dirt/pebble caught between brake pads and rotor? Bad CV joint?
is it 4 wheel drive?yes