The Sierra and Silverado share a platform but they’re not identical. Suspension tuning is different, some trim levels have different brake specs, and the electrical systems diverge especially on the Denali.
If you’re using a Silverado manual for your Sierra you might be working with the wrong torque values. Happened to a buddy of mine on a control arm replacement — wrong specs, wrong ball joint preload, alignment was off by 1.5 degrees.
What’s in the Sierra factory manual:
- 5.3L and 6.2L engine specs specific to Sierra calibration
- Magnetic Ride Control diagnostics (Denali only)
- MultiPro tailgate wiring and actuator specs
- Max Trailering Package tow rating breakdown
- AT4 off-road suspension torque specs
2022 GMC Sierra OEM factory manual here. All years from 2004 on the site.