Need help finding a 4.10 LSD (be nice im new)

[Sagaris]

Hi, this is my first post here. I am new to BMW's and have mostly owned and dealt with my former S14 240sx and Mk2 Vw's. I have been researching and lurking the forums for the past few days reading up about differentials.
I currently have a 1991 325i with the grandma differential in it ( see also open diff). I did some calculations with gear ratios and have decided that I would rather run a 4.10 LSD rather than the 3.73 which the 325is has (from what I understand). It looks like the 318is and the 325ix are the only cars with the 4.10 differential ratio. So it is time for me to find a rear diff which also means that it's question time:

1)Does the 318is have a 4.10 limited slip? Wikipedia says its an open diff. EDIT: ANSWER: Looks like the 318is does not have a factory LSD. and 4cyl and 6cyl cars do not have interchangable diffs ( due to output flange differences) with the exception of the e30 m3.

2)Is the 325ix rear differential a VLSD or a clutch type? EDIT: ANSWER: It is different than the 2wd cars, (either helical or viscous, still not sure. so I know I dont want one from an ix since I want a clutch type.

3)What do the markings look like on the diff case that tell me that I am buying a LSD and where are they located? pics would be great! EDIT: ANSWER: There is a white "S" painted on the outside case.

4)What is the diff fluid of choice? ( assuming redline but im not sure about lsd additives)

5) Do you have any suggestions on checking the condition of an LSD while it is out of a car, I dont think I could tell the difference between a completely spent diff and a properly functioning one on my own.


Dont worry fellas, I'll buy a Bently soon enough :p I would really appreciate some feedback in the meantime. Thanks! -Sagaris


oh, and rule #1
The ole S14, and thats a chassis code, not an engine code for you M3 folk

[Sagaris]

btw I just stumbled across this which has great information for anyone else, http://www.e30eta.com/ecdiff It has answered a few questions I have but I still appreciate any further input. It looks like I will be searching for an M3 diff. unless I can find a cheap good condition 3.73 LSD nearby.

[White325is]

U.S. E30s:

318i/is

1984-1985 - 3.64 (84 open for Auto)
1991 - 4.10 (Manual)



318ic

1991-1992 - 4.27 (Manual w/ LSD option)


325

1988 - 2.93


325e/es

1984 - 1985 - 2.79 w/ LSD option
1986 - 1987 - 2.93 (es = LSD)


325i/is/ic

1987 - 1988 - 3.73 (is = LSD)
1988 - 3.73 (Automatic; iS = LSD)
1989 - 1993 - 3.73 (Manual; is = LSD)
1989 - 1992 - 4.10 (Automatic; is = LSD)


325iX

1988 - 3.91
1989 - 1991 - 3.91 (Manual)
1989 - 1991 - 4.10 (Automatic)



M3

1988 - 1991 - 4.10
1988 - 1991 - 4.45 (rare)


325i Touring

3.91 (LSD = option)

[Sagaris]

ORLY!?! So I can find a 4.10 LSD from a 325is Automatic ! Thats good news. Thx for sharing that!

[lifeiskaos]

paypal me $250 shipped (assuming you are from the U.S.) and a 4.10 LSD will magically appear at your door.

[e30m20beast]

that's a nice KA on the 240 keep it up

[e30trooper]

that's a nice KA on the 240 keep it up

sure is hua... wanna go KA-T? I have a topside turbo manifold for DOHC ka's :D 100bux NEW

[Sagaris]

I am going to look at a 4.10 LSD tomorrow and the guy doesnt know what it came out of exactly. How can I tell if it is a Viscous LSD from a 325ix or if it is a clutch type from a 325is? Is there something to look for on the serial number? I know the LSD should say S4,10 but I am not sure if the viscous lsd has something different to look for.

[DaveSmed]

It will have a "V" in place of the "S". I wouldn't worry about it too much, they are fairly rare.

Also, 4 cyl diffs and 6 cyl diffs are interchangeable, but do have differences. The 6cyl diff is physically larger and is a stronger diff. The 4cyl diff has slightly longer flange stubs to make up the size difference.

Both were available in LSD, even in the 318is. LSD was optional across all models, standard in the sport models.

[Sagaris]

I have found another differential that the seller claims came out of a 1987 325is Automatic it has an "A" stamped on it



Has anyone seen an "A" stamped or know if this signifies anything different?? thanks

[nando]

I think '87 325is automatics came with 3.73s anyway

what you want to see is the diff tag.. that will have everything on it.

[Sagaris]

He says that he swapped the diff covers with an ES diff he used to have so the tag is incorrect and the car he put the correct diff cover on is long gone so thats no help.

[xwill112x]

I think '87 325is automatics came with 3.73s anyway

what you want to see is the diff tag.. that will have everything on it.

the auto's came with the 4.10 ratio.

[kishg]

the auto's came with the 4.10 ratio.

only 88+

[Sagaris]

The orange+banana pic in your sig is hilarious! :P there is a lot of jumbled info on the interwebz about the 325is autos being 4.10 for all years or just 89-91. I will have to manually verify that when I go to see it.

ALSO: the seller says the diff has low miles , alluding to the fact that the previous owner of the car it came out of, had it replaced so that throws another wrench in the spokes of trying to figure out whats going on. When all is said and done I think I will clean this thread up and put some correct and helpful info in it for future posterity.