ok in my 98 m5 i have 3.23 gears. im pretty sure i dont have limited slip because it will only spin one wheel. well i have gotten it to spin both on 2 occasions and that was on very smooth blacktop. is their a code for lsd cuz i wanna find out what i have.

 

G80-limited slip

You probably do have posi. It gives power to the wheel that has more traction, this could be why the other times you only saw one mark. My friend has a peg leg truck and it always does one mark.

 

i just looked. no g80

 

see for your self,
Go to howstuffworks.com and look up differental and look at the picture and then look up zexal-torsen after that blows your mind then pull off the diff cover of your car and see what you have.
A regular diff and stock limited slip look way different.
sounds like you don't have limited slip to me.

 

so limetid slip = posi?

And where can i find the code?

 

Limited slip is the same as posi. The RPO numbers are on the inside of the drivers door on the door jam.