I Know this is the xj section but I have an 06 wk 3.7l v6 engine. Sludge is all over the oil filter and the plastic shield underneath it. Also all over the transmission pan and pretty much under the whole front end. Any idea of the cause?

 

Do you do the changes yourself ? If I'm thinking correctly the oil filter is just above the differential on the 3.7l 4x4 and it is very easy to spill oil all over the differential and down the skid plate .. If I were you I would degrease and wash the underside and watch it closely

 

I just changed the oil it was because the oil filter was not screwed on tight