Need help identifying Diff asap

[Brandon12V]

My input shaft on 3.73lsd needs rebuilt(pictured right). unknown diff was given to me by a friend. when I rotate the input flange, both output flanges rotate the same direction. when I rotate the one of the output flanges, they go opposite. if def seems longer than my 3.73. roughly 1/2 to one full turn on the input flange to meet the ratio. I judged this off of 1 full rotation by the output flange while turning the input flange. please help. I'd like to get this figured out before I decide to put it in my car.

grazie



-Brandon

[Brandon12V]

Ok I went back and marked them to make rotations. my diff is definately a 3.73lsd. I did the rotations on it and there were three full rotations plus 3/4 rotation. roughly 3.75 so 3.73. the other diff was 4 full rotations plus roughly 1/5 rotation..........???? thoughts?

[Brandon12V]

fuck it. I'm putting it in. it's either a 3.93 or a 4.10... one question... what should my RPM's be at 60mph if it's a 4.10?

[TimR]

3200 ON MY VERT. WITH 4.10 lloks like you got a open left/LSD right trust me you will like the extra pull with the 410

[Brandon12V]

oh my god... it's a 4.27 diff. shouldnt take long to blow this thing up, lol.

[TimR]

If you got 17's it will run like 373 due to the tire height.

[cabriodster87]

small case on the left

[jdvorwe]

was it free?

Definitely a nice pick up.

[Brandon12V]

not free. got it for 30 bucks tho. going to an e30 restoration guy to see if he has a 3.73 sittin around for trade. just curious but has anyone actually tried a 4.27 with an m20?

[Brandon12V]

I took the cover off. it is open. what did these come on? I know the medium case is more common. were these originally equipped on m10's?

[acolella76]

If you got 17's it will run like 373 due to the tire height.

wheel size isn't going to affect anything, it will still have the stock outer diameter

[Jaxx_]

i don't think we got 4.27 smalls in the US, i looked it up and it was 316s and M40 318s

[Brandon12V]

could be the case but even so, this could have easily come across the pond. After I rang a memory in my buddy's head, he knew I was right. He got the diff from a guy named Joe who owns Superior Auto here in town. Before opening his own shop, Joe was a master tech in Germany. I'm sure he brought some things back to stateside with him.

[Jaxx_]

could be the case but even so, this could have easily come across the pond. After I rang a memory in my buddy's head, he knew I was right. He got the diff from a guy named Joe who owns Superior Auto here in town. Before opening his own shop, Joe was a master tech in Germany. I'm sure he brought some things back to stateside with him.

JDM TYTE, YO! :up:

[Highway1]

dude it even says 91 318i on the diff. All 91 318i verts came with a 4:27.