The inner filter doesn't need changing in most cases unless the outer filter has failed. I change my outer filters once a year but they need it. I don't go to the dealer though. Try looking at a local truck parts place like TruckPro. I get Donaldson filters @ about 25% dealer price.
Yup after reading posts in this thread, the $50 inner filter went back to the dealer......... I did install the outer filter & probably didn't need to....
I'll have to do a search for a Donaldson dealer............ :cheerful: