Hey guys i just signed up and the website is awesome. I need some advice on a diff swap however, i just bought a 1200 sedan and the hubs on the driveshafts are buckled so i figure the best thing to do is to replace the whole diff. I read the tech section and i feel my best option is the 120y borg warner diff with the 120y tailshaft to match. I tried to look into a thread explaining what is invlolved but i couldnt find anything... dont get me wrong the tech section is awesome i would still be looking for a standard 1200 diff today if i hadnt found this website, but id like to ask if anyone knows if it is easy as said? does it bolt straight in with the tailshaft? does the 120y diff have to be a 1968 BW model? does the 120y have to be manual?... sorry for the bucket load of questions but if anyone could help out with some info it would be greatly appreciated keegan

the 120Y BW diff assembly will bolt into the 1200, but there are a few little things to watch out for.

1) you will need the U bolts and plates under the springs. The 120Y U bolts will be longer due to the bigger leaf pack and the rubber insulators around the leafs, but I'm 99% sure I used them - it was a lot of years ago...
2) being a 1200 sedan you won't have any shock mount probs if you take the 120Y shock mount plates too.
3) get the handbrake cables with the diff too - just unscrew at the adjuster and it will fit up to the 1200 no worries.
4) also get the brake lines on the diff. just remove the flexible line at the junction on the diff housing.
5) if your sedan is a manual, you will need a 120Y BW manual tailshaft. If the sedan is auto, you will need a 120Y BW auto tailshaft.
6) the holes in the spring mounting plates on the diff of the 120Y are larger than the 1200 because of the metal encapsulated rubber insulator things on the 120Y. I found some washers the right ID and OD at the local nut and bolt place to fit to the spring's through bolt. I would not use the 120Y rubber insulator things when fitting the diff to the 1200 - they will be well past their use-by date and might lead to axle tramp problems. plus they will lower the car a bit and you would need the 120Y through bolt with the spacers and stuff that go up into the rubber. you would also need to modify them to fit on the 1200's 3 leaf pack - 120Y has 5.

That's about as easy as a bolt in conversion will ever get.

oh, you might want to trim a bit off the bump stops if your car is pretty low, but i can't remember the sedans bump stop setup now - probable on the shock I'd guess

you might find the bolts hard work to undo if you are removing it yourself. clean the U bolt's threads with a wire brush before you try to undo them. and a bit of WD40 will be a help too. as will a decent breaker bar or better yet, rattle gun...

awesome reply thats exactly what i needed thankyou so much