Wix lists their oil filter 51324 for the 4D55 2.3L turbodiesel. I found that also fits all the other Ram 50 gas engines as a larger upgrade to the Wix 51381 normally spec'd for those -- effectively identical filter specs aside from the size and 5 psi higher burst pressure for the 51324, reckon they spec the larger filter for the diesel to deal with soot getting into the oil.

I had no trouble ordering the Wix 51324 from O'Reilly's a year or so ago, still in stock there and at Amazon:




As for the air filter, Fram lists their CA4369 for the 4D55 2.3L turbodiesel, which x-refs to the Wix WA6019, Purolator A43583, Champ/Luber-Finer AF4368, and K&N E-2871. I'm seeing those in stock online here: