Between the engine and the hydraulic pumps on a Volvo excavator sits a geared adapter housing that transmits crankshaft torque to the pump train. The parts trade calls it several things at once: power take-off, PTO group, pump coupling, bearing housing or pump drive group. It is not a pump and not a motor, and when its bearings or gear wear, the symptoms look like a hydraulic failure while the cause is mechanical drive loss.This section covers replacement pump drive housings and PTO assemblies for Volvo EC excavators, including the 11128611 and 15054375 groups. Send the machine model, engine designation and serial prefix when ordering, because the housing differs by engine family. Our pump drive and transfer case failure guide covers how to test this assembly before replacing it.