Challenge: ID this LSD

[EN318isPDX]

So I got this diff used from someone and they told me it was a 4.10 but I am seriously confused because it has 7 numbers and 1 symbol ^..

[Farbin Kaiber]

322s?

[EN318isPDX]

322s?

That was my first guess but I can't seem to find any cars that came with 322

I was told its a medium case from an autotragic

[reelizmpro]

Looks like a replacement diff. I don't know why they don't use the same tags.

[EN318isPDX]

Looks like a replacement diff. I don't know why they don't use the same tags.

How do you mean?

[shiboujin]

The first numbers on the tag are "441" and the last letter is an S. So I'm going to say it's a 4.41LSD.

You can always spin the input shaft and do the math to figure out the ratio. And you can spin one axle stub to see if it's an LSD. if the other side spins the same direction, it's an lsd. If they spin the opposite, it's an open.

[Jaxx_]

^this

if it's an LSD it should also have a white S painted on it. obviously not as quite as definitive as spinning the shafts...

[EN318isPDX]

The first numbers on the tag are "441" and the last letter is an S. So I'm going to say it's a 4.41LSD.

You can always spin the input shaft and do the math to figure out the ratio. And you can spin one axle stub to see if it's an LSD. if the other side spins the same direction, it's an lsd. If they spin the opposite, it's an open.

What car came with a 4.41?

[drumad]

318ti

[EN318isPDX]

318ti

And is it a direct bolt on?

[shiboujin]

I really have no idea where the diff came from. Emotech had a sticky on it but their DB is down. If it's from a 318ti, it theoretically will fit. Maybe need light mods?

[EN318isPDX]

I really have no idea where the diff came from. Emotech had a sticky on it but their DB is down. If it's from a 318ti, it theoretically will fit. Maybe need light mods?

Ok cool well i got it from Joe Funk, and he isnt a noob. So if he said its a 4.10 i want to believe him but the tag is mighty confusing! I will be swapping it out for a small case 4.10 than ill be able to crack it open and find out

[reelizmpro]

What car came with a 4.41?

4.41 doesn't exist, 4.44 (4.45?) does but that's not what this diff is.

From the Bentley:

For replacement final drives, the code also has the drive ratio and manufacturing number. However, the ratio is given indirectly, by the number of teeth on the ring and pinion. For example 11 38 A 405 is an exchange final drive with ratio of 3.45:1 (38 ring teeth divided by 11 pinion teeth). The A indicates replacement diff. S indicates limited slip.

Your tag is slightly different but this makes sense: 41/14 = 2.93, which does exist. The tag or cover may have been swapped also. Only sure way is to pull the cover and count some teeth.

[drumad]

4.41 doesn't exist, 4.45 does but that's not what this diff is.



From the Bentley:



For replacement final drives, the code also has the drive ratio and manufacturing number. However, the ratio is given indirectly, by the number of teeth on the ring and pinion. For example 11 38 A 405 is an exchange final drive with ratio of 3.45:1 (38 ring teeth divided by 11 pinion teeth). The A indicates replacement diff. S indicates limited slip.



Your tag is slightly different but this makes sense: 41/14 = 2.93, which does exist. The tag or cover may have been swapped also. Only sure way is to pull the cover and count some teeth.

Crap, my mistake. As soon as I saw 4.4 I instantly reacted with 318ti.

4.44 is def from the 318ti and should be direct bolt on. Pretty sure the output shafts are the same as well......

BTW, as mentioned before, can't you also just spin the input and compare the output shaft rotation?

Hopefully this is right.

1. place a reference mark on the input and an output shaft along with corresponding marks on the diff itself.
2. spin the input 360 degrees
3. measure how much in degrees the output moved (it'll be less than a full rotation)
4. use this formula

ratio = (360/degrees_measured) : 1

quick and dirty table with random ratios
ratio........output shaft theoretical
2.93........~122.8 deg
3.45........~104.3 deg
4.10........~87.8 deg

I did this quickly in my head, someone please correct me if I'm wrong.

edits: way too many -_-

[EN318isPDX]

Suppose to be picking up a small case 4.10 LSD this week than ill be able to bust it open and count how many teeth are missing! :P