<!-- from fixya rte -->How do I fix diff rancher in astro van 2003 - 2003 Chevrolet Astro

what was your test to determine the failure ?
if you jacked up one end and the car didn't drive off the jacks , that is how an all wheel drive works
It has a differential in the transmission that allows the front axle to drive at different speeds to the rear ( same as one wheel on the axle will go faster than the other when going around corners)
it is used to prevent torque wind up in the drive train and destroying transmissions , diffs and drive lines
it has to have all 4 wheels on the ground so that the 3rd diff is not operational unless going over a speed bump or dips in the road
however if you have a 4 wheel lock for the transmission, that is different as it locks up the 3rd diff in the transmission making the car a 4 x 4

If the shaft is spinning then you have either a hub or shaft spline issue or the joint is bad or shaft is popped out of joint in the rubber boot.

get a Haynes repair manual

What makes a car AWD is the fact that there is a diff in the transfer case in the gear box . This allows the front diff and the back diff to operate at different speeds from the road surface just as one wheel can go faster in turns than the other side.. To say that the AWD is not working would mean that it is not going any where as the rear or the front will have no drive because the diff will not be operating as a diff.

this may be coming from an axle"{ wind up" situation occurring when the diff between the front and rear diffs is not working properly. If you have traction control I would suspect a faulty sensor. Have the fault codes read to make sure

Could be that you need to add a lil more fluid to it.

try to tap on the blower motor with the switch in the on position the motor is located on the passenger side close to the firewall if it kicks on you need a new blower motor

Well you fix it yourself then. You will need axle stands, an ebay diff and a weekend. I did this job on a Toyota Estima 4x4. Get stuck in there :-)

try these websites www.alldatadiy.com and www.autozone.com and i would also like to give you this information they sells only GM-parts Schram auto & truck parts 1-800-292-1032 and website www.schramauto.com wish you the best of luck Michigan Man.

Typically newer vehicles run at a normal operating temperature of 195 degrees to 205 degrees. if anything it's running a cold, which would waste fuel.