Irregular shifting and slight lack of power along with a rattle
At low speeds of 15-25mph, hard shifting occurs, at speeds above 45-50mph, the odometer drops from 3,000 rpms-2,000 rpms and the truck slows down, but if i press on the gas any, the rpms do not move and all i hear is the engine working harder but no reaction to the road, also when this happens, a rattle occurs. If i let off the gas and press again, the truck reacts with acceleration but does the same thing again.
What is wrong with my truck guys?? I took it to autozone and got it checked by the computer and no codes were shown but there is clearly something wrong.