I cleaned up the baffle tray that sits in the bottom of the sump at the rear, screwed down by four 5/16-18 UNC X 1/2" hex head screws.
I’m not sure if this is C.2392 for the flat bottom sump, or C.2392/1 for the stepped bottom sump.
I noticed it has 6 spot welds across the center, holding nothing.
I suspect there was a baffle plate in there, which has gone awol.
By the oil marks it looks like it was there for awhile before departing.
I had the same problem: the aluminium baffle plate C.2342/1 (spot-welded to the tray) had apparently separated from the tray and taken out by a PO. “Happens all the time”.
I made a new baffle and used pop-rivets this time to fit the baffle. Note the cut-outs at the bottom for the ribs of the sump. I even stamped the number on the baffle (just for fun). I then could screw the complete assembly in the sump.
I see you have the same dipstick marks around the dipstick clearance hole that I have; not quite enough clearance there. Well I guess it shows that somebody checked the level quite often. Or they failed to get it in all the way and it rattled around in there for awhile
Would like to disagree with you on that: many modern aluminium car bodies are spot-welded nowadays, often called Resistance Spot Welding (RSW) with very sophisticated equipment like water cooled copper electrodes.
In recent years, research work by aluminum sheet suppliers and automotive companies has overcome many of the original problems with RSW of various types of aluminum alloy sheet, so that today it is used in production of various automotive vehicles. For example, GM has introduced its patented multi-ring electrode design for use in the RSW of closure panels on various high volume production vehicles.
You can even buy Aluminum spot welding equipment for the DIY segment.
It is possible to join aluminum sheet metal with a standard spot welder - I’ve done it several times. First you clean the surfaces to be spot welded with a stainless steel brush. Then rather than attempt to spot weld the two sheets of aluminum directly you need only sandwich them between two additional strips of 20 ga steel before clamping the 4-layer sandwich in the welder and pulling the trigger. Works a charm.