My 1975 120y 2door manual has diff problems.I have a spare diff from a 75 4door auto.The question can I swap the auto diff straight into the manual. Both cars are stock standard.your help appreciated....Baz

All 1975 Datsun 120Y's sold in Australia used the same differential. They all have a 3.9 to 1 ratio.

thanks for the advice Dodgeman, thats what I like about this site, helpfull members thanks

just check the 2 diffs together and make sure they look the same just in case your spare diff is a borgwarner(australian diff) the japanese diff on the 120y's are the h150 and have a sump plug in the middle just to the right, check the tech section under drivetrain then go to "which lsd,diff to use and it has a couple of pics
http://datsun1200.com/modules/nsectio ... p?op=viewarticle&artid=30