olice: :box: I have tranny grinding issues, and have done some reasearch on the topic. Seem this issue goes way back, affects not only our Si's but older ones, Acura CL, TL, TSX, Type-R, Etc. Many have switched to the GM Syncromesh, with or without FM (friction modified). After purchasing some myself, and speaking with a GM top level mechanic, he suggested also using an additional friction modifier for the LSD on our cars. Others cite that when they added an LSD to their cars (ones that doesn't come stock), some had to add this additional modifier for the LSD. Please note that the "friction modified GM Syncomesh" is only modified for gear wear, not LSD clutch packs!!! I have read many posts on this, and nearly all fail to mention the additional modifier that I feel is necessary. So I will also add the LSD modifier as recommened by GM. Any opinions/counters to this opinion? Anyone had trouble with their LSD after making the swap to GM, Amsoil, or Redline MTF?