Re-torque to eliminate clunk

Some owners of 2007-2010 Chevy Silverado and GMC Sierra vehicles may complain about a clunking noise at the rear of the vehicle. The cause may be excess movement at the rear suspension leaf spring area.
The noise may be resolved by re-torquing the joints of the leaf spring assembly.
1. Support the vehicle at curb height (for example, on a drive-on rack). Do not remove the fuel tank.
2. Loosen the shackle joint at the frame, front eye joint to the frame, rear eye to the shackle joint and the anchor plate U-bolts.
3. Re-torque the shackle joints to the frame and to the rear eye (tighten the shackle nuts to 73 ft.-lbf.).
4. Re-torque the anchor plate U-bolts (1, 2, 3 and 4) to 74 ft.-lbf.
5. Re-torque the front rear spring mounting nut to 148 ft.-lbf.
6. Repeat Steps 2-5 for the opposite side.