Axle carrier / subframe
Provides mounting points for suspension and drivetrain assemblies.
Under the front or rear body.
The carrier locates arms, steering or drivetrain mounts and transfers their loads into the body.
A structural workbench underneath the body.
Corrosion, impact damage or mount movement needs structural inspection.
Wear is condition-based and strongly affected by roads, loads, impacts and seals. There is no universal replacement mileage.
Links and bushings are smaller repairs than complete adaptive struts or air-spring systems; alignment may be needed after work.
BMW rear axle carriers and the body mounting area are separate structures with different repair considerations.
BMW passenger cars and SAVs; spring, damper and axle design depend on chassis and options.