[Broke_as_****]

Easy way to tell if the car has LSD, if you can jack it up:

Spin one of the rear tires by hand, if the other one spins opposite, it is an open dif. If it spins the same way, it is a LSD.

You can find out if the car has LSD if you have the model number.

From 240sx.org:

Here is for the S14 (95-98)

S14: Checking for LSD using Car's Model number

Find the car's identification plate on the firewall, passenger side.

Check digit 18 in the model # (not the VIN!).

For Feb '94 - July '95: A, C, or E, = LSD

F, or "-" = NO LSD

For July '95 - July '96: A, C, or F = LSD

B, D, or "-" = NO LSD

Here is some more links that help with figuring out how you can get a LSD in your 240.

http://www.240sx.org/links/installs/lsd2/index.htm
http://www.240sx.org/links/installs/lsd/lsd.htm