when it shifts from 1st to second, it jerks REAL bad, should i get th fluid replaced, about how much does that cost?

 

Are your shift points still at the normal time or are they now late? If they are normal then you could have a broken 1-2 accumulator spring. This can be replaced at the same time as a fluid and filter and would cost under $100 to have done. If the shifts are also late then you probably have a sticky throttle valve in the VB. I would suggest a TransGo Shift Kit to permanently fix this.