Help Me Identify a Differential I Just Bought?

[mrnine]

I need some help. I ordered what is supposedly a limited slip 3.45 differential from a 318ti for $450 shipped.

When I spin one side, the other spins in the opposite direction. Some people have told me that it should spin the same way. Some people say that's not true and that only under stress will the differential actually lock.

Upon receiving it, I checked the tag and it does not have an "S."

http://rich.mediabrite.com/318ti/opendifftag.jpg

Okay, I'll give it the benefit of the doubt; perhaps someone changed the cover, right?

But, I know for a fact that LSD's would also have the "S" painted on the diff. I rubbed off the grime and found a distinct "N."

http://rich.mediabrite.com/318ti/painted_n.jpg

My suspicions are that this is an open diff. Can someone please confirm, if nothing else, than a painted "N" denotes an open diff?

If not, what is going on here? The person I'm dealing with is very nice and just got the diff shipped me from a different yard in Chicago. My guess is that the Chicago yard has made a mistake. My feeling is that they are going to come back with a VIN# and claim that that confirms that it's a locker.

Can anyone help me out?

[DustenT]

If it spins the opposite direction, it's an open diff. Trust me, I removed an open diff from my 1997 auto and installed a LSD from a 1995 club sport. The 3.45 small case differential with LSD spins in the same direction.

[andyman7931]

If it spins the opposite direction, it's an open diff. Trust me, I removed an open diff from my 1997 auto and installed a LSD from a 1995 club sport. The 3.45 small case differential with LSD spins in the same direction.

+1, LS diffs should always spin in the same direction...

[mrnine]

Well, everything I had read told me to expect them to spin the same direction. The guy selling me the part told me that "On some of the newer cars because of the electronic traction control, the axle will not always spin the same direction on the other side, like the older vehicles would. If the differntial is a LSD then it should function as an open diff unitl you have a loss of traction on the main drive whel, then the LSD will lock up the rear end." It seemed that I had read something along these lines at some point.

So my leading indicator seems to be no S on the tag. Second sign is each side spins opposite. So what's up with the "N" painted stamp?

[AlaskaBlue]

+1, LS diffs should always spin in the same direction...

That is what mine does. So uh +1 more.

[DustenT]

Well, everything I had read told me to expect them to spin the same direction. The guy selling me the part told me that "On some of the newer cars because of the electronic traction control, the axle will not always spin the same direction on the other side, like the older vehicles would. If the differntial is a LSD then it should function as an open diff unitl you have a loss of traction on the main drive whel, then the LSD will lock up the rear end." It seemed that I had read something along these lines at some point.

So my leading indicator seems to be no S on the tag. Second sign is each side spins opposite. So what's up with the "N" painted stamp?

It's an open differential dude. e36s don't use an kind of electronic differential traction control.

[mrnine]

It's an open differential dude. e36s don't use an kind of electronic differential traction control.

Uh...ASC+T? This isn't effectively "electronic traction control?" Though I suppose it works by limiting power to the engine when it senses slip, so it's not "differential" traction control, true. And it seems by design alone, the LSD should result in simultaneous similar rotation of axle shafts mechanically, not electronically. Most everything I've ever read confirms what you guys are saying. I'm just trying to sort it out.

And I am correct that LSD combined with ASC+T isn't going to present a problem, right? It was offered together as an option, right?

[96cali]

Uh...ASC+T? No?

ASC+T uses the individual ABS brake channels to slow down one or more wheels as needed. That's why swapping your diff out does not mess up traction control. It's two different systems.

[mrnine]

ASC+T uses the individual ABS brake channels to slow down one or more wheels as needed. That's why swapping your diff out does not mess up traction control. It's two different systems.

OK. That makes sense. Thanks for the explanation.

[DustenT]

And I am correct that LSD combined with ASC+T isn't going to present a problem, right? It was offered together as an option, right?

I have ASC+T and LSD, no problems here. The two systems work beautifully together.

[roadrash]

For more info on Differentials and ASC+T, have a look at the Notebook section of your favorite web site:
Differentials (http://www.318ti.org/notebook/diffs/index.html)
ASC+T Explained (http://www.318ti.org/notebook/asc/index.html)

HTH... HAND....

JMJ

[mrnine]

I'm having a hard time getting this vendor to listen to me; he's convinced that this is not an open diff. Here's what he says:

I called the dealer and had them run the VIN from the car that this
differential was removed from. Here is the VIN: WBACG7325VAS99529

This car came equipped from the factory with the "M" sports package and did
have a locking differential. Please call your dealer and have them confirm
this information for you. When I spoke to my dealer he put me on the phone
with their head service tech and he told me that he had never heard of the S
stamp being the identification for a locking diff. I am not saying your
information isn't accurate, but my BMW store doesn't know about it. Thanks,
let me know what you find out.

Wasn't an LSD only an option on the club sports? Or could it be ordered on any year? There's no difference between what the vendors refer to a "locking" differential and a "limited slip" differential, is there?

Sorry for amateur questions. Just trying to sort this out.

[jetblackbimmer]

I might be be wrong.

Clubsport LSD was part of the package., not offered on other 95s. Became standard on sports and active and an option on base, after 96. Like I said I may be wrong.

[tastade]

And again, with my LSD, they both turn the same direction. when I turn one wheel when both are off the ground.

The LSD for the BMW is a clutch type unit, the clutches are usually engaged and only slip when a substantial amount of force is applied to them like in a turn where one wheel is spinning faster than the other. That is both should rotate the same direction and at the same speed until the gripping power of the clutch has been exceeded. It is certainly not an LSD.

[DustenT]

I'm having a hard time getting this vendor to listen to me; he's convinced that this is not an open diff. Here's what he says:



Wasn't an LSD only an option on the club sports? Or could it be ordered on any year? There's no difference between what the vendors refer to a "locking" differential and a "limited slip" differential, is there?

Sorry for amateur questions. Just trying to sort this out.

I ran that VIN, it is for the 1995 318ti. On realoem, it shows two versions, one with LSD and one without.
http://www.realoem.com/bmw/showparts.do?model=CG73&mospid=47506&btnr=33_0385&hg=33&fg=05

Also, keep in mind that it might not be an original diff in that car, maybe it was swapped out. Tell your guy that you NEED one the spins the same direction.

[AlaskaBlue]

I was of the opinion that 1995 was the only year the ti had the option of the LSD. I know my 95 active was optioned with an LSD.

[96cali]

I might be be wrong.

Clubsport LSD was part of the package., not offered on other 95s. Became standard on sports and active and an option on base, after 96. Like I said I may be wrong.

According to the notebook link Roadrash posted and my memory, LSD was available until ASC+T came out in '96. After that the LSD was not available, or maybe if you factory deleted ASC+T which few average people would do (have LSD but not ASC+T).

MrNine- I have a 3.45 LSD and photos of it if that will help explain what itshould look like. I think I have a closeup of the label too. PM or email me.

[tastade]

I called the dealer and had them run the VIN from the car that this
differential was removed from. Here is the VIN: WBACG7325VAS99529

This car came equipped from the factory with the "M" sports package and did
have a locking differential.


That certainly isn't from a 95 club sport or "m" as it doesn't have the right serial numbers. The club sport serial numbers are around 53600. It could be a 1996 or later sport package, but did they have LSDs? It sounds like they didn't from what others are posting.

edit: It is from a 1997, I wish I could find out more...
http://www.bmw-z1.com/VIN/VINdecode-e.cgi

http://www.318ti.org/forum/showthread.php?t=3007&highlight=club+sport+serial+number

If you call a BMW dealer you should be able to get the option codes for that VIN.

[DustenT]

That certainly isn't from a 95 club sport or "m" as it doesn't have the right serial numbers. The club sport serial numbers are around 53600. It could be a 1996 or later sport package, but did they have LSDs? It sounds like they didn't from what others are posting.

edit: It is from a 1997, I wish I could find out more...
http://www.bmw-z1.com/VIN/VINdecode-e.cgi

http://www.318ti.org/forum/showthread.php?t=3007&highlight=club+sport+serial+number

If you call a BMW dealer you should be able to get the option codes for that VIN.

I must have typed it in wrong in RealOem. A second look reveals it to be:

8/97 - Date of production.
You Have Selected: P E36 com
318ti M44 USA
19970800 L M
Production Code: CG73,
batch ID: 47506

The problem with getting parts from recycler is that they use a cross reference database. I'm sure their program indicates that it will FIT, but will it PERFORM the same? No. You need to find a LSD diff from a 1995 Club Sport TI if you want a direct bolt in. I paid through the a55 for mine.

[Kzach]

Okay dude I just received a LS 3:45 from Bavarian for my 98 318TI and just like all the other posts it spins in the same direction. Tag reads R345V2251. At that price you quoted, I am betting it is a open drive. My cost $600.00.

[bmw318tiChic]

Where exactly are you supposed to look for the "s" that denotes if you have an LSD or not? Does someone have a picture, or a good detailed description? Thanks :)

[m3outtanowhere]

ASC+T uses the individual ABS brake channels to slow down one or more wheels as needed. That's why swapping your diff out does not mess up traction control. It's two different systems.

actually. It uses the Wheel speed sensor/pulse generator to tell a main computer the rotation speed of each tire. If it senses a faster rear wheel...it closes a throttle plate and loses power to the wheels (cuts off the air to the motor through the intake).

[DustenT]

actually. It uses the Wheel speed sensor/pulse generator to tell a main computer the rotation speed of each tire. If it senses a faster rear wheel...it closes a throttle plate and loses power to the wheels (cuts off the air to the motor through the intake).

ASC+T is a two part system. One part is as described above, a butterfly closes off air to the motor to slow it down (the ECU may pull timing at this time too). The second part is as described two posts up, the brakes are applied to the wheel that is slipping. You generally only feel the braking portion when sliding through a corner or when stuck in deep snow.

[1996 328ti]

Where exactly are you supposed to look for the "s" that denotes if you have an LSD or not? Does someone have a picture, or a good detailed description? Thanks :)http://i44.photobucket.com/albums/f23/vasa58/diff11.jpg
http://i44.photobucket.com/albums/f23/vasa58/diff6.jpg

[bmw318tiChic]

Thanks Steven :) So there should be an S where the R is?

[1996 328ti]

Thanks Steven :) So there should be an S where the R is?S would be LSD. I suppose R is open.

[mischief]

then what dose the white N mean
and have you tryed removing the cover
to see if ts an open or LSD

[pdxmotorhead]

Take the back cover off, take a picture send to vendor.

There is no way to mistake them once opened....

Dave