Ok, I got my tranny rebuilt about 2 years ago, but didn't get it installed till feb of this year. I've run it about 30 miles and it shifts like crap. The only way it'll shift up is with my foot flat on the floor and the motor wound way out, then it does with a huge jerk. Downshifting is sporadic, sometimes it does right, sometimes it has to be done manually. Need to know what to do here. Fluid's fine, tranny's out of warranty. Do i need a new rebuild or is it something simple?