GoneDragRacing.com

What trans fluid/gear oil do you guys use in manual transmissions for a mustang..T5..tremec..etc

Some people use 10/30..some use syntec 80/90w.

What is the best as in breaking down and smoothest?

WC t5's 85 and newer do not take gear oil. Same goes for tremec transmissions t5's take atf Dextron III I will only run GM synchromesh in my tremec tko or 3550 same goes for the 500/600 series.

gear oil I use royal purple 75W90