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]

Originally Posted by 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.

+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]

Originally Posted by andyman7931

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

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

[DustenT]

Originally Posted by 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?

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

[mrnine]

Originally Posted by DustenT

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]

Originally Posted by mrnine

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]

Originally Posted by 96cali

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]

Originally Posted by mrnine

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
ASC+T Explained

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]

Originally Posted by 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:



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...85&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.