95 firebird

I have a few problems, but the number one thing is when i am driving, my transmission doesnt seem to be the problem, but when i am going from 1st to 2nd my tires like kida spin and makes a clunk noise, but i am not running it hard enuff for it to spin, i actually have to let it shift on its own, like i let off the gas when i know it tring to go to 2nd, and the clunk isnt so hard, but after 2nd no problems at all, does anyone have any idea what could be the problem, its kida mysterious to me cause i have had cars where the transmissions slip but this one isnt slipping i dont think... thanks any ideas welcomed :)

Sounds like your trans might have a shift kit. it'll make it shift harder when you get on it. have you had this car long?

also look at your transmission bushing i had to replace mine, it was clunking anytime there was alot of load on the transmission: i.e. hard on the gas from a dead stop. or any hard shift.