I got better shifting out of a hurtin' T5 by using 1/2 Valvoline ATF and 1/2 synchromesh. Made about 70 passes down the 1/4 AFTER it started popping out of 1st and grinding badly into 1st and 2nd, and still works to this day. I'm runing a fresh T5 now, just regular Valvoiline ATF in it, works great.