I just bought an '07 3500 w/5.9l Cummins and went to go change the fuel filter because I don't trust folks that say they've done any maintenance recently. I got a new fuel filter (Baldwin PF7977, before you ask, I don't want anyones opinion on the filter I choose to use, just let me do me. No offense. I researched them quite thoroughly and everything I could find said this or the Fleetguard 19800 was the right one.) Anyway, I get the filter cap off (yes, I have the right tool for the job, Lisle cap socket) replace the old filter and go to put it in and wouldn't you know it, the cap is about 1/8th in. too tall. I remove the filter from the cap to make sure there is nothing in there, there wasn't, so I tried again. Same result. I go the auto parts store, get a WIX filter just to check and same problem. I got a new filter cap, tried it with both filters, same result. I removed the rubber plug/gasket from the bottom of the filter and it got a little closer. Checked the fuel bowl, I can't feel anything that would be stopping the filter from going all the way on. Any ideas?