Have a 2001 Yukon XL Denali with 50K miles. Yesterday was turning out of the driveway when the power steering completely failed after a short 1 second "loose belt" noise. Serpentine belt OK, and power steering fluid level OK (although the power steering fluid has a Burnt electrical smell).
Any thoughts? Extremely difficult now to turn steering wheel, both stopped and moving.

I think you'll find that your power steering pump pulley shaft is broken.

Reach in and try to move the pulley in and out.

Also, you can remove the serp. belt and spin, pull, and move the pulley shaft in and out (looking for play in shaft).

Hope this helps.

Same thing happened to my GMC Yukon. Pulley shaft broke.

Thanks - my local dealer confirmed that it is a broken power steering shaft. Does $400 for a new pump and $100 labor estimate seem reasonable?

hell no they ripping you off!

And that's why I'm through with GM.

im through with gm too! too expencive on their own people

Before you spend any $$ check for a recall. A new recall was just issued for broken hydraulic pump shafts. An excerpt from NHTSA.com site is below...

Summary:
SOME PICKUP TRUCKS, VANS, AND SPORT UTILITY VEHICLES EQUIPPED WITH A HYDRAULIC PUMP DRIVESHAFT THAT CAN FRACTURE, RESULTING IN IMMEDIATE LOSS OF HYDRAULIC POWER STEERING ASSIST. ON CERTAIN VEHICLES EQUIPPED WITH HYDRO-BOOST POWER BRAKES, THE SAME CONDITION CAN RESULT IN LOSS OF POWER ASSIST FOR BRAKING AFTER THE RESERVE PRESSURE IS DEPLETED.
Consequence:
AN INOPERATIVE PUMP CAN CAUSE INCREASED STEERING EFFORT, AND IN HYDRO-BOOST EQUIPPED VEHICLES ALSO INCREASED BRAKING EFFORT, BUT DOES NOT COMPLETELY ELIMINATE THE ABILITY TO STEER OR SLOW THE VEHICLE.
Remedy:
DEALERS WILL REPLACE THE HYDRAULIC PUMP. THE CAMPAIGN IS EXPECTED TO BEGIN DURING FEBRUARY 2005. OWNERS SHOULD CONTACT CHEVROLET AT 1-800-630-2438 OR GMC AT 1-866-996-9463.
Notes:
GM CAMPAIGN NO. 05001. THIS ACTION IS DEEMED A SAFETY IMPROVEMENT CAMPAIGN AND IS NOT BEING CONDUCTED UNDER THE SAFETY ACT. THE COMPANY HAS INFORMED NHTSA THAT IT WILL PROVIDE THE MODIFICATIONS DESCRIBED ABOVE FREE OF CHARGE.

I hope this helps.

Yeah,

Just my luck. Mine broke on our '02 xl in October. Maybe I should forward this to our extended warranty company.

But I was lucky...mine broke while it was at the transmission shop getting a new transmission and they were starting it to test the tranny.

Nope...I know what you are thinking...they only repair trannys there.

Did I mention that I am quite happy we have extended warranty? Still cost me $50 bucks though.

Later, Mike

gm sucks