Bought my 98 XJ recently with oily residue all over the underside including filter, starter, and trans pan. Valve cover had a lot of oil near the rear so replaced with fel pro gasket and then wiped the underside drips. It's been sitting for a week without running and now there's fresh drips on the filter and the bellhousing. Thinking filter adapter rings and RMS?​​​​​​​

 

There is no "classic" rear main seal leak.
There is the "classic" misdiagnosed leak.
Do the RMS absolutely last. Here's why: https://cruiser54.com/?p=96

 

After sitting for a week and droplets developing on the filter, I'll definitely replace those o-rings. I suppose I can still drop the oil pan to see/clean inside the pan and replace that gasket and see if those plus the valve cover have fixed the leak.

 

why drop the oil pan? fix known leaks and wait.

 

You seemed determined to pull the pan on your recently acquired xj to "take a look" but before you do that pita process do the following:
Flush cooling system
Replace all coolant hoses and the belt
​​​​​​Clean/ refresh the grounds

Do a couple drain/fills on the transmission

Carefully inspect brakes and brake lines

Install headlight relay harness
replace battery cables
replace plugs, plug wires, cap , rotors
Clean throttle body
Replace any worn front suspension/ steering parts

Probably forgot something but you get the picture

 

Thanks guys, just thought it would be worth it to pull the pan during first oil change. PO provided extensive maintenance records and most things mentioned above have been serviced or replaced in the last 2 years, but I'll still inspect all systems as I go.

 

I'll pile on. Do the filter adapter first. Pulling the pan isn't as easy as it sounds, and there's not much to see in there anyway.

 

If you have to pull the pan is a stock height XJ, it helps to let the suspension droop and support the frame. You can unbolt the shocks for more droop if needed. It's much easier on lifted rigs.