D8 2U oil pan gasket

I am looking for some advice on my 2U.

I need to drop the oil pan and also remove the oil filter system from the side of the block so I can clean everything out.

The parts book shows the following gaskets:

Pan gasket, rear: 1F4090
Pan gasket, front: 1F4089
Filter base to oil line manifold: 7B4034
Filter base gasket: 7B4520

I called Caterpillar this morning and they said all four gaskets are no longer available.

For those of you who have done this before, what has worked best? Should I plan on making new gaskets out of sheet gasket material, or have any of you had good luck using RTV silicone sealant in these locations?

I would rather do it right the first time while everything is apart. Any advice on gasket material, thickness, or sealant that has worked well would be appreciated.

pictures for reference.

My best guess is that your parts person did not add an "O" or zero to the parts number? I have been told that the old part number needs to have extra #'s? Someone help me here. Olson's Gaskets should have what you are looking for.

Part numbers changed but the later numbers are also obsolete.

Thank you Juiceman and Brian, I appreciate the help.

I did reach out to Olson Gasket to see if they can make something up for me. I was also able to get the gasket between the two oil pan sections from Caterpillar, so that at least takes care of part of it.

If I strike out on the rest, I will plan on making the remaining gaskets myself.