Overhauled high performance pump as used in the last DS23! For vehicles with semi-automatic transmission. 5 409-758 CAUTION: Please clean the entire hydraulic system before installing an overhauled hydraulic unit! Our cleaning fluid (Art.-No. 308910) is recommended for this purpose. In particular, also clean the storage tank in which the dirt from the last 45 years has been deposited. After installing the hydraulic pump, first fill it with LHM / LHS via the suction hose. If the above advice is not followed, a warranty claim can be rejected!