when i got my jeep i replaced the valve cover and was never able to get the correct grommet for that, would end up with a grommet that either fit the valve cover right or the plastic filter box right (the thing you described has a bunch of filter elements in it as i found when mine fell apart).. anyways since then i have now found a parts catalog... looks like it should be part number "5300 4721" can't guarantee as the catalog is also for Cherokees which used a different crank case ventilation system... but it also has all the parts for yjs....