GMC Repair: 2001 yukon denali - ignition lock - steering lock, yukon denali, pontiac buick

Question
Hi,
  I have a 2001 yukon GMC Denali. Today I went to start it and the key would not turn. I noticed the steering wheel was not locked also.
 after about 30 minutes of trying both keys I have - jiggling - turning the wheel - trying to put it in neutral, rocking the car and moving the tilt up and down, i went to get the WD 40 out.

That did not work,so I got the air compressor out and tried shooting some wd 40 is then rushing air in. After  awhile of that not working I decided to jack the front end up. Since the wheel was not locked even with the key out I thought maybe turning the wheel back and fourth my do something. with out the front end jacked up I could turn it but it was VERY difficult since the car was stationary.

 After jacking the yukons front end up I managed to get the key to turn and start the truck after turing it as far to the right as possible a few times.

 NOW the wheel is still not locking when I shut the ignition off.  not sure what is wrong. I am thinking this might happen again but I might not be so lucky as to be in my driveway next time so I want to get this fixed.

I was wondering if you might know what I need to buy - what it is that is broken or any help at all would be appreciated.
I'm not the kind of person that goes to dealerships, I have generally been able to fix things on my own.  Just a little confused on this one and on a limited budget.

Thanks a million if you can help.

Answer
It sounds like you have a Lock Cylinder that has gone bad. The only GM product I have not seen this in with any frequency is Cadillac. However, Pontiac, Buick, Oldsmobile, Chevrolet I have. It is most common in the "throw away" cars. I seen this problem in 50% or more of the GM vehicles.

 Back to your problem. If the cylinder goes bad the wheel will not lock. I am assuming you were very lucky this time. Estimated cost depending on where you are and what the markup is at the particular auto parts retailer you go to...you are looking at $180-$200. If you do not have a steering wheel puller (or adapter) for wheels with air bags, you will need one. Make sure you check the signal mechanism and wheel locking mechanism on the steering shaft.