The clunking intermediate shaft on the 2000+ vehicles can be a major annoyance. This procedure will walk you through lubing the shaft, or if a replacement is purchased, how to install it.
READ THE ENTIRE PROCEDURE AND CAUTIONS BEFORE STARTING! PART OF THIS PROCEDURE GOES AGAINST GM'S RECOMMENDATION REGARDING MOVING THE STEERING COLUMN. IT IS BELIEVED THAT THE PROCESS USED HERE IS NO DIFFERENT THAN NORMAL STEERING, AND SHOULD NOT CAUSE PROBLEMS. THIS PROCEDURE HAS BEEN USED ON 2 VEHICLES, WITHOUT PROBLEMS. NEITHER THE AUTHOR, NOR STAFF OR MEMBERS OF THE FORUM ASSUME ANY RESPONSIBILITY FOR DAMAGE OR INJURY INCURRED BY FOLLOWING THIS GUIDE.
What is needed is:
an 11mm wrench or socket for the steering gear pinch bolt.
a 13mm wrench or socket for the steering column nut
a 7mm wrench for removing the hush panel
a panel clip removal tool, or a pair of wire cutters
If lubing the shaft, your choice of grease. I'd suggest some type of thick grease, like wheel bearing or CV joint grease.
If you are planning to replace the shaft, the part number is 25810450 as of late 2011. (Thanks to yourgrandma for the updated part number.)
A drop light.
Start with the wheels pointing straight ahead. Open the hood, then look down toward the bottom of the firewall under the brake booster for the lower boot that covers the lower part of the intermediate shaft where it attaches to the steering gear. Push it up and in toward the firewall.
This will allow you to get to the pinch bolt that holds the intermediate shaft on the steering gear. It's a 11mm bolt. Remove the bolt, and set it aside in a safe place.
Moving inside the car, remove the hush panel on the driver's side. This is held on by 2 7mm screws, and a panel clip. This shows one screw and the clip.
If you do not have a panel clip removal tool, you can carefully pry it out with a pair of diagonal wire cutters.
Caution - Use care when dropping the hush panel, as it holds the driver's side interior temperature sensor (for dual automatic controls) and the driver's side floor lamp. Once the panel is down, twist counter-clockwise to remove the temperature sensor (if equipped).
Then unclip the connector for the light.
Looking under the dash, above the brake pedal, you'll see the inside boots covering the bolt for the upper U joint to steering shaft connection. If dealer work has already been done, it is likely that at least the black boot has had a slit cut into it - like this one has.
If the boot is already slit you're all set. If not, you may want to take a box cutter and cut about a 3 - 4 inch slit in the black boot. (Some have said that it is possible to push the clear boot down far enough to reach the bolt. You may want to try that first.) Start by pushing the box cutter through the boot, about in the center. Then push down and away from you toward the end of the boot. This keeps you away from wiring, and lessens the likelihood of injury if the knife slips. Once the boot is slit, and opened up, you'll be able to see the bolt that holds the top part of the shaft. (The vise grips are there to hold the slit open enough to get a picture.)
The bolt has an arm attached to it to keep it from spinning while the nut is removed, so do not attempt to remove the bolt. The nut will likely be on the top side (away from you) of the shaft. It can be reached with a swivel-head box end ratcheting wrench, although not easily. A small handled socket wrench will reach it also, again not easily. To make the nut easier to reach, start the car, and turn the steering wheel clockwise about 1/4 turn. Turn the engine off.
You should now be able to see the nut, and get a 13mm wrench on it to remove it. Be careful not to drop the nut while removing, as it is likely to fall inside the clear boot and be hard to retrieve.
Once the nut is removed, and before removing the bolt, start the car again and turn the wheel counter-clockwise to straighten the wheels. Shut the engine off. This should allow you to easily remove the bolt. This is the nut and bolt.
Caution - From this point on, until advised differently, the steering wheel must not be moved from it's current position. Any major movement will cause misalignment once the steering shaft is reinstalled, and could damage the steering position sensor.Slide the top connection out of the steering column, and push it down into the clear boot as far as it will go. Move back under the hood, and lift up on the lower U joint near where the pinch bolt was to remove it from the steering gear. It should move easily. If it resists, slide a screw driver under the joint and lift up. Once it is off the gear, work the shaft down out of the boot. This is the shaft removed.
If you are replacing the shaft, you may skip over the next section on lubing, and move on to the the installation.
The shaft is two pieces - an outer section and an inner. The outer section is the top part of the shaft, and has a hole where the inner shaft slides.
Squirt, shove, or push the grease down into this hole, then find something to cap it off. A cork, plug, or even a nitrile gloved thumb will do. I used a small sink drain plug, and then my thumb.
Hold the plug in place (if the right size, just twisting the U joint on its side may hold it well enough) and then slowly work the shaft in and out several times. You may wish to add some more grease, and work it in again. This allows the grease to work its way through all of the splines. This is an old shaft that has been taken apart to show the splines.
Eventually, you will see the grease starting to work its way out the bottom of the outer shaft.
Check the movement of the top U joint. If it does not move smoothly, work some grease or motor oil into the bearing caps.
To reinstall, clean the excess grease off from the shaft, and compress it.
Working from under the hood, push the shaft up into the boot. You will likely have to adjust its position several times before it slides in.
Slide the intermediate shaft back onto the steering gear making certain that where the pinch bolt goes in is facing forward.
Install the pinch bolt and tighten to 35 ft lbs., lower the boot over the steering gear, then move back inside the car. You'll have to reach down into the clear boot inside to pull the shaft up, then align it so that the top part slides inside the steering column. This will take a few attempts before it all lines up.
Slide the bolt into the shafts, and try to hold it in place, while starting the car and again moving the steering wheel clockwise about 1/4 turn. Put the nut on the bolt and tighten to 33 ft lbs.
As the hush panel doubles as an hvac plenum, when you reinstall, make certain that the duct on the hush panel
lines up properly with the duct under the dash and behind the floor column (if equipped).
Install the driver's side temperature sensor, reconnect the light, install the screws and panel clip and you're done!