I have the same issue and there is a TSB for it. On mine, I can feel/hear it at the front bumper.
Snap/Popping Type Noise Coming from Front of Vehicle (Remove Bolt-In Front Crossmember and Add Washers) #03-08-61-002G - (Feb 14, 2006)
Snap/Popping Type Noise Coming from Front of Vehicle (Remove Bolt-In Front Crossmember and Add Washers)
2003-2006 Cadillac Escalade
2003-2006 Chevrolet Avalanche, Suburban, Tahoe
2004-2006 Chevrolet Silverado
2003-2006 GMC Yukon, Yukon XL
2004-2006 GMC Sierra
1500 Series (½ Ton) and 2500 Series (¾ Ton) with Two-Wheel Drive
This bulletin only applies to 1500 and 2500 series 2WD vehicles with recirculating ball type steering.
This bulletin is being revised to add the 2006 model year, update the correction information and change the quantity of parts needed. Please discard Corporate Bulletin Number 03-08-61-002F (Section 08 -- Body and Accessories).
Condition
Some customers may comment on a snap or popping-type noise coming from the front of the vehicle. This condition is most apparent during hard left or right turns at low speeds. Going over bumps while turning may also aid in producing this noise.
Correction
Remove the bolt-in front crossmember and add washers using the procedure listed below.
Important: DO NOT slot the mounting holes on the crossmember as stated in previous bulletins. Slotting the holes has been found to be less effective and, in some cases, causes the noise condition to be more prevalent.
1. Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle in the General Information sub-section of the Service Manual.
2. Remove the mounting nuts, bolts and the front crossmember from the vehicle.
3. Clean all the undercoating off the crossmember in the area of the mounting holes.
4. Reinstall the crossmember with the bolts and nuts. On the driver and passenger side, add washer P/N 11509592, or equivalent hardened washer (see dimensions below), at each bolt head and nut location.
Tighten
Tighten the bolts to 120 N•m (89 lb ft).
5. Apply an even coat of Anti-Corrosion Coating, P/N 12346501, or equivalent, to the crossmember where removed. Overlap the original coating in order to provide an effective corrosion protection.
Inside Diameter Outside Diameter Thickness
14 mm (0.551 in) 35 mm (1.38 in) 3 mm (0.118 in)
Parts Information
Part Number Description Qty
11509592 Washer 8
