6 INCH FILTER KIT FOR 4 INCH SUMP
This filter kit if for Allsion 3000 and 4000 Series Transmissions with a 4" Sump. It contains the gaskets and o-rings you need to change the filters.
 
Go to https://allisontransmission.com/parts-service/my-transmission and enter your Allison Serial Number. Group 16- will give you the Sump description for your transmission.