So currently i'm running Amsoil 5W-30 synchromesh in my TR3650. I know what you're thinking already, "ughhh another f*cking transmission lube thread!"... When the transmission is warm, the shifting is smooth as one could expect. However when it's cold, that is a completely different story. I was reading up on the different fluids used in these wonderful vehicles of ours, and saw a lot of the T56 guys use synchromesh and add a friction modifier to it for smoother shifting. I was wondering if it would be safe to do the same for our cars? What kind of friction modifier would you get anyway? Like one for a limited slip rear or something of that nature?