Clunking sound on x300

When driving over a bump there is a solid sound clunk that seem to be under the drivers seat. I have check and the seat mounting is solid. Car steers well, does not roll. Car is going into winter storage tomorrow . Would like to get some suggestion as to what to look for next spring. I thought it might be shock or/ and struts. Any info would be greatly. Appreciated

When I worked at the dealer I had a 1995-1997 X300 sedan come in for a noise under the passenger seat and it turned out to be a broken gearbox cross member mount assy.

The aluminum bracket was completely broken.

The right side was resting on the exhaust pipe and that was the only reason the cross member was not ‘scraping’ the ground!!!

Check the mounts including the rubber at the rear of the gearbox?