I am still trying to figure out what parts I need, from what year and model car(s) to convert my 90 780 to a 3.31 rear axle, and get rid of the Nivomats. Today I found a 92 (8/91 production date) 960 sedan at the local wholesale auction. The differential was clearly marked 3.31, but I could not crawl far enough underneath it to tell if it had a conventional U joint or a CV joint at the pinion flange. Unfortunately, this car has Nivomats, so it would not provide the parts necessary to eliminate them, which makes it difficult to justify buying the entire vehicle just to get the differential, as there is very little else on it that I have any use for. The car has about 200K miles, body decent, interior a lot less so, won't start due to a dead battery, oil cap is missing, and it looks pretty grimy inside the cam cover. The only other good thing about it is four almost new (cheap) tires. Based on previous sales I've seen (and bought a few of) I estimate it will go for around $500, which, if it had all the suspension stuff I'm looking for, might actually be worth it, but as it is, it's not.