Is there anyway to tell the difference or what to look for between a stock GSR transmission and a LSD? ITR transmission? not sure if thats right but thanks anyways!

Im saying this because my gears squeek only in 1st, 2nd and 3rd gear but the rpms have to be really low and friends thought it might be a LSD transmission. thanks alot.

 

when u look at an ITR tranny with LSD, you see this big ol' stamp on the tranny saying "LSD"