As i am accelerating from 25-35 mph the vehicle almost feels like it doesn't want to shift into next gear. the vehicle sort of jiggles/jolts while trying to gear up. once reaching 35/40 mph then vehicle runs normal. if i push down on gas peddle to make car go through that gear, the engine revs up and the vehicle kind of jolts a "get up and go" feeling and the rpms go above 4k, which then vehicle gets up in speed and moves. once at 35/40 mph, then the vehicle runs smoothly.