After vehicle is driven some distance and vehicle is hot the awd is binding up you can feel it as you drive around roundabouts and when you go to park and turn to full lock it binds up and make a clunking noise

Depending on the specific vehicle many 4WD have a transfer case that will lock the front and rear drives shafts together. This configuration is only for slippery conditions like ice and snow or very wet or off road. When turning the radius is different between the front and rear so there is a lot of feedback to the steering wheel. This is created by the fact the front set of wheels and the rear set of wheels must make the same number of turns because of the locked transfer case.

If you attempt to drive on high friction surfaces the stress to the drive train is excessive and will cause damage. The whine and the bunny hop is the drive train attempting to release this tension. If you were on a slippery surface the tires would have much less resistance turning at slightly different rates.

Also critical is the tire size need to be the same. However even with perfectly matched tires the problem on dry surfaces remain the same.

The AWD vehicles are equipped with a third differential that allows for the difference between the rotation of the drive shafts so it can drive on dry pavement no problem. Some configurations allow the AWD to have the transfer case locked which falls into the first category where dry pavement is prohibited.

Some Jeeps have a viscous coupling in the transfer case that permits limited slip between front to rear but the resistance to slip increases as the deference increases as in the event one tire is slipping
These Jeeps still have the lock up option in the transfer case requiring dry pavement when engaged.

Hope this helps?

With an AWD vehicle there is a diff in the transfer case that allows different speeds between front and read axles . If you have 4wd button (lever ) that allows the diffs to be locked for slippery /off road conditions then it can be driven with out the front drive shaft if you have it in 4wd. If you do not have that option then without the front drive shaft it will go nowhere.

The vehicle is always in AWD and that cannot be altered . There is a 3rd diff in the gear box that allows independent operation of the front and rear wheels to prevent drive line wind up . When you select 4WD you lock up that 3rd diff so that both front and rear axles have to turn. This results in drive line torque wind up so the vehicle must not be driven in this mode on hard surfaces as there is no means for the wheels to slip and relieve the torque wind up . To loose the wind up reverse for several yards and any actuators that are trying to move will be able to or drive on slippery surfaces to allow the wheels to slip

Sound like you may need a new power steering pump or rack and pinion. Have you noticed any leaks from the vehicle? If you've had the vehicle for 21yrs, then I would have to go with the power steering pump is begining to fail. Hope this helps.

Yes...
The tire sizes are important on any 4X4 vehicle... IF you engage the 4X4 ... or is you have an AWD vehicle...

If the tires are different sizes , front and rear... then the front and rear axles will turn at different speeds... not in sync with the gearing of the transfer case.

Unless this vehicle is being driven on snow , ice or mud.... while in 4x4 mode... this is very bad.... for axles and transfer case...

The problem is likely the transfer case has locked up, the question is do you need it to continue to be an AWD vehicle? If not a simple solution is to remove the driveshaft from the transfer case to the front differential case. Takes maybe 15-20 minutes and there are no leakage issues by doing so. The vehicle will now be a rear-wheel only drive one. I recently did this to our own 2003 model and as the car stays in the south, there is no need for the AWD. The car performs as expected and that binding problem is gone.

the jeeps with awd or full time 4wd have a viscous coupling in the transfer case that transmitts power to the front axle when the rear looses traction. if the tires on the jeep are mismatched or the tires are not properly inflated it can engage the awd thus forcing the front and rear axles to turn at the same speed. when turning, the front wheels must turn faster than the rear because they are following a wider arc than the rear, this causes binding in the drivetrain which is releived by the tires slipping on the pavement sporradicly. the viscous coupling is filled with fluid that, when heated by the friction of the input spinning faster than the output, locks the coupling. a mismatch in tire sizes or tire inflation can produce just enough heat to lock the coupling in summer, but not in winter. to make a long story short, these vehicles are very sensitive to diffeneces in tire diameters.

The fluid in the versa trak AWD in the rear is old and needs to be drained and refilled. After you drain and refill it, make a bunch of sharp left and right hand turns, then drive it for 10 minutes. Drain and refill it for the second time and problem solved. Use only versa trak fluid available at any GM dealership.

the trailblazers are designed to shift from 2 wheel to AWD on the fly. BUT NOT TO EITHER OF THE 4 WHEEL OPTIONS. I'd suggest you get it to a mechanic to evaluate the damages.
Jer

  The clutch in the transfer case is burnt up and fused together therefor binding the powertrain. If you continue to operate it like this it will destroy the front differential and possibly the rear differential. It was most likely cause by the tires not having equal circumference either due to a mismatch of tires (different brands although the same size is indicated on the side wall will have different measurements,I have seen BF Goodrich tires have a different size because speed rating was different although the model was the same) or lack of tire rotation during the life of the tires.. If the measurements are not with in 1/4 inch around the center of the tread this will cause your concern. Tires should always be replaced at all 4 corners on all wheel drive vehicles.