That's what were trying to point out...
If your gonna run a auto behind the i6, you will need a flexplate, not a flywheel....a flywheel is for a manual trans setup with clutch and pressure plate bolted to it....
What your trying to do never came from the factory,so you wont be able to just go to the store and buy the parts you need...its been so long since they made the i6 that parts are scarce in the junk yards also, so it may take alot of searching....the 4l80 bellhousing should bolt up to the i6 no problem...there will be one bolt that cant be used though...with a flexplate on the i6, I'm not sure how the 4l80 torque converter will work....I know on gas burners there is a .400 difference between a LS and SB that has to be made up when mixing old with new..just not sure about how the diesel was setup...
Also the 4l80 torque converter bolt pattern wont line up with i6 flexplate holes..so you'll need to elongate the holes or drill new ones
A flexplate for a 292 is no problem to find on google..heres one....
https://www.12bolt.com/store/p123/Flexplate_292.html