how to tell if you have limited slip diff?

[Paradox]

Just wondering
I just bought a 1990 325ic - breifly going through the forums it seems like all convertables came with a limited slip diff mines an Auto so I guess it would be 4:10 - but is a LSD?

How do I tell?

Thanks

[george graves]

There is a metal tag on one of the bolts(?) that will tell you the ratio, and if it's a LSD or not. If it is it will start with an "S". So, S373, or S410, ect...You'll most like need to clean it very well before you can see it.

There will also be painted on the top of the diff big S about 2-3" tall. You can't really see that when it's in the car.

Oh, there's also some trick that you can jack the car up and spin one of the wheels and the other one will move in the opposite direction or something - but I've never done it that way.

[jlevie]

A simple check for a working LSD is to jack up one side of the car, place the transmission in neutral and try to turn the wheel that is in the air via the axle nut. A good working LSD will require 50ft-lb to turn the wheel. If it requires little to no force, either you don't have an LSD or it's clutches are worn out.

[slammin.e28]

If it's open, the wheels will spin opposite directions.

If it's LSD they will spin the same direction.

[Paradox]

thanks guys!