September 30, 2005
The MDV minimum pressure valve and its O-ringed end plug found in VW and Audi 01J and 01T units prevent the transmission oil pump from drawing in air from inside the transmission case when the engine is started. Additionally, when pump output is high, the MDV minimum pressure valve opens to allow excess oil volume to return to pump suction, bypassing both sump and filter. This results in an increase in overall efficiency.
Problems symptomatic of a worn MDV minimum pressure valve/bore are delayed engagement and slipping in either Forward or Reverse. These issues are the result of lost critical oil pressure due to air pulled into the pump at engine start, oil leaking directly to the sump, or cross leaks between adjacent circuits. Reconditioning the bore and installing Sonnax oversized MDV minimum pressure valve kit 33741B-14K restores optimal pump efficiency through renewed hydraulic integrity.
Sonnax valve body layouts provide a detailed overview of individual units making it quick and easy to determine what’s available for the specific valve body you’re working on. See all Sonnax valve body layouts.
Vacuum testing at the port(s) indicated fails to hold the recommended minimum in-Hg, or if wear is visually detected.