Front wheel bearings on the GMT800 platform are a sealed hub assembly unit — not a traditional serviceable bearing. On most 1999–2007 Silverados they develop noise between 80k–130k miles. They are straightforward to replace but easy to misdiagnose.
SYMPTOMS
- Humming or growling noise that changes with speed
- Noise shifts or disappears when turning — load transfer onto the bad bearing masks the bad one
- Ticking or popping noise when turning at low speed
- ABS light on — the wheel speed sensor is built into the hub
HOW TO DIAGNOSE
- Test drive at 30–60 mph — listen for growl that changes when you swerve left and right
- If noise gets louder when turning RIGHT — left front bearing is bad
- If noise gets louder turning LEFT — right front bearing is bad
- Jack up front wheels — spin by hand — feel for roughness or play
2WD vs 4WD
- 2WD uses a simpler hub — cheaper, easier to find
- 4WD (with ABS) uses a hub with an integrated encoder ring
- 4WD hub: torque to 177 ft-lbs (2003+) — under-torquing causes premature failure
REPLACEMENT STEPS
- Loosen lug nuts before jacking
- Remove the caliper and rotor — support caliper with a hook
- Remove the three hub bolts (usually three 15mm or three 13mm bolts on the back of the knuckle)
- Pull the hub out — it may require a puller on rusted applications
- Transfer the ABS sensor connector if equipped
- Install new hub — torque to spec