recently my truck starts to jump out of gear and feedbacks on what may be wrong

 

Without knowing what trans it has, how many miles, what maintenance/repairs/mods have been done & when, how long the symptom has existed and what happened just before, or any other details, the possibilities are endless. GIGO Help us help you by providing as much relevant info as possible. Take a minute to fill in your profile & create a signature with your truck's details, both in your "User CP" linked at the top L of every page. If you're not sure about the details, post some pics & read your VIN number. The caption of this diagram contains links that will help: