2006 Chevy Silverado

Hi gpipher. Welcome back to the forum. This sounds like it might be similar to a problem Dodge Neons had. In an effort to lighten the vehicle, the steering column housing no longer goes through the firewall. Instead, just the rotating steering shaft goes through a rubber seal. That seal is what was squawking. You might have to remove a protective cover, then use a hooked tool such as a cotter pin puller to pull the boot back. Spray some grease on that boot / seal where it contacts the shaft. Chrysler has a lithium-based "Spray White Lube" that works great. It is available from other manufacturers too.

Let me know if I'm off base and I'll delete this reply and let some smart people respond.

Caradiodoc

Just so I'm clear, it makes this noise all the time, right? If the noise is gone when the engine is not running, that points to a noisy power steering pump. GM has had a lot of trouble with noisy pumps on cars but I haven't heard about that on trucks.

Caradiodoc

Here is a service bulletin regarding the power steering pump.

Power Steering Whine Noise - keywords fluid gear hose idle pump turn - (Mar 4, 2008)

Subject: Power Steering Whine Noise

Models: 2003-2006 Cadillac Escalade, ESV, EXT

2003-2006 Chevrolet Avalanche, Suburban, Tahoe

2003-2007 Chevrolet Silverado Classic

2003-2007 GMC Sierra Classic

2003-2006 GMC Yukon, Yukon Denali, Yukon XL, Yukon XL Denali

2003-2007 Hummer H2

This PI was superseded to update models and Recommendation/Instructions. Please discard PIT4208A.

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Condition/Concern:
Some owners may comment of a power steering pump whine noise. After normal diagnostics you may find the noise to be coming from the power steering pump. This whine noise is most commonly heard between idle and 2000 rpm coming from the power steering pump.

Recommendation/Instructions:
GM Engineering has not evaluated this product, but reports from GM Dealers of flushing and refilling the power steering system with Valvoline SynPower Power Steering Fluid have reduced or eliminated this noise. Valvoline SynPower Power Steering Fluid is a synthetic fluid and is available at most auto parts stores in quart size containers. In most case 3 or 4 quarts will be needed to flush and fill the system.

If Valvoline SynPower Power Steering Fluid is not readily available, replace the power steering pump ordered from GMSPO only. Power steering pump improvements have been made which will help eliminate this noise and are currently available from GMSPO. Use the parts catalog to look up the correct part number for your application.