Lazrrdgt90

I have a 2000 GT Convertible with the 4R70W auto and lately its been shifting really rough into 2nd gear from a dead stop, and when im doing 25 mph or less it wont shift into O/D, it jerks the car a bit trying to tho, however it will shift into it when i get up to 35mph or higher. And another concern was a weird noise it started making when i come to a complete stop, like a popping/slight grind noise comming from the torque converter area which goes away when i accelerate again. I want my tranny to run like it used to but i dont have alot of money to spend on it. I checked the fluid as well its fine and still good. What do you guys think is going on? Will it have to be rebuilt?