1990 Chevy S-10 clutch, transmission? both?

i have a 90 chevy s10 and when i got it the clutch worked pretty good it has a 4cyl rearend so the gears are shorter i think anyways i think the clutch is going out well im 90 percent sure. but i drive it still when i first start it up and drive it it grabs pretty good but i cant give more then a 1\4 gas pedal or it will slip then start to grind...i was told by a mechanic that my tranny takes only syncromesh gm fluid and that my tranny would go bad if i used other wise... the fluid in the tranny is a different fluid so im pretty sure that could be part of it im about to buy the clutch but if the trannys bad or a fluid change cant fix it then i want to get a new tranny before i put it all back together
what do you think?[img:de2770e937]http://www.2carpros.com/forum/automotive_pictures/143328_front_blue_1.jpg[/img:de2770e937]