Pump drive shaft with internal flow tube and method of installation

A method of increasing hydraulic fluid flow within a pump drive shaft of an automatic transaxle, said pump drive shaft having an internal flow tube therein forming an axial fluid passage between an outside surface of said flow tube and a longitudinal bore of said pump drive shaft, said axial fluid passage being disposed in fluid communication with a plurality of fluid ports having longitudinal axes and formed within said pump drive shaft such that hydraulic fluid flows through said axial fluid passage and around said flow tube independently of hydraulic fluid flowing within said flow tube, said method comprising the steps of:

• providing a replacement flow tube having a non-cylindrical cross-section;
• inserting said replacement flow tube within said longitudinal bore of said pump drive shaft such that a modified axial fluid passage is created between said flow tube and said longitudinal bore;
• and
• positioning said replacement flow tube in predetermined angular relation to said fluid ports such that said modified axial fluid passage is disposed in proximity to said fluid ports providing increased fluid capacity therein.