If it is a Freightliner and Cat 350 like mine it takes a cannister. I have an Itasca Horizon 2002. This is not a refill for a filter like you may be used to it is the entire cannister.
Get the information from the chassis mfg. Parts stores will get you the wrong thing every time, at least they did for me.
You could also call a local RV Shop they could give you the information and order the filter for you.
Hang on to your wallet and thank goodness you do not have to change it with every oil change.
An RV'r is someone driving a $300,000.00 Motorhome towing a $40,000.00 car and looking for a free place to park.