Grave dig.
My chain is close to totally stuffed now.
You can't bolt in the D21 case in Australia to a D22 as we didn't get the V6 4x4 like the US market did, and the spline count is different between D21 4-bangers and D22 4 and 6-bangers.
I'd argue it's not any stronger anyway - I've inherited both a stretched-chain D21 case and a stretched-chain D22 series 1 (early) and neither of them was rock crawling, just driving on hard surfaces in 4x4 would be my assumption. No lockers in either.
So the solution is to just keep replacing it with another D22 case.