synthetic fluid in motor and trans?????

[m3summ]

hey guys just curious if anyone has changed out there manual transmission fluid for some kind of synthetic oil. i have an 06 g35 coupe 6mt. my second gear always feels weird while shifting, almost a slight grind, dealer says there is nothing wrong with it. i was thinking maybe some synthetic oil may help. has anyone done this, im looking for pros and cons and results. also figure ill switch out the motor oil at the same time i have 5500 miles on the car thanks.

[infinititech1]

i've replaced a few transmissions for gear grinds. if you have 5500 miles i would hope nothing is wrong with the transmission...