Some AL4 and maybe DPO transmissions are now fitted with a NDTH hydraulic distributor. For these applications there is a paper gasket used in the valve body. This gasket must be replaced during each repair/overhaul.Failure in changing the gasket will result in drivability problems and shorten the life of the transmission. For further Info, please ask for "IDS-DPO(AL4)-V/B-Gasket". This gasket is not part of our Overhaul kits - please order separately - A 11 27 FD023 DPOAL4.