Carrier Bearing
A center support bearing that supports the middle of a multi-piece driveshaft on longer-wheelbase vehicles.
A carrier bearing, also known as a center support bearing, is a structural support component used on vehicles with long wheelbases, such as trucks, SUVs, and large rear-wheel-drive sedans. Because a single, long driveshaft would whip and vibrate at high speeds, manufacturers split the driveshaft into two or more sections. The carrier bearing is bolted to the vehicle's frame, housing a ball bearing that supports the joint between the driveshaft sections.
The bearing is encased in a thick rubber isolator block to absorb drivetrain vibrations and allow for slight movement. Over time, the rubber isolator can dry rot and tear, or the bearing itself can wear out and lose its grease.
A failing carrier bearing causes symptoms like a low-frequency hum or vibration under acceleration, a squealing noise at low speeds, or a clunking sound when shifting gears or taking off. Replacing the center support bearing involves separating the driveshaft sections.