Oil Pan gasket replacement.
 

I had my 400 on the ramps this weekend changing the oil. The car wasn't high enough for me to get all the way under it and back to the oil pan. Will I need to remove anything like a cross member to remove the oil pan or are all the bolts accessible..

There is no oil pan gasket on Toyota or Lexus cars so the leak is most likely coming from somewhere else and working it's way back to the pan area.

Don't think I have a leak. Just thought I would do a little preventive maintenance on a 20 year old car. Please explain no gasket. I did see where the bolts are to remove the pan.

They almost never leak as they are held in by silicone FIPG remember it's a Toyota not a Chevy so the same rules far maintenance do not apply here.

If it aint broke then don't fix it best applies to Lexus, I found out the hard way myself.

yeah with the toyota pan's they usually won't leak until you mess with them cause of the FIPG.
on the 300 you undo the motor mounts and lift the engine up to get the pan out without removing the engine, but Im not sure if thats even possible on the 400, probably similar though.

Summary: I wouldn't ever touch it before it starts leaking, your rear main seal will leak long before the pan does.

I will not mess with it. Thanks guys.

Or front main or cam seals. Those like to leak too.