i am not sure what lsd this is the main gear has 66 teeth from what i been reading its itr or ctr but i am not really sure hope someone can help me out i also want to know if its oem

 

ITR/CTR.

 

is oem can i use this lsd on my gsr trans if so i have to use the gsr big gear right

 

It's OEM. You'll have to shim the diff (it's far easier to do this if you use the enclosed ball bearings instead of the taped roller bearings still on the diff) I can't remember if the GS-R ring gear is the same bolt pattern or not. Aquafina could tell you for sure. I'm going to move this to the transmission/drivetrain section, you should get better responses there.

 

It is an OEM ITR or CTR 94-96. The 66 tooth ring gear is the same on the GSR, ITR and CTR 94-97 JDM and 94-01 USDM