Hi guys, I recently purchased a 2009 Avenger SXT V6 about 4 months ago. For the first month or two every so often the car would kinda throw me back while driving. Sorry I dont know the correct terms trying my best to describe everything to you. Anyway now its doing it every single time i go past 60 it has a bit of difficulty switching gears to get up to 70 and will some times worse then others throw me back a bit and the engine will rev loud before it switches at times.

i have brought it back to the dealer multiple times since I bought it and he says oh theres nothing wrong with the car the car is perfect blah blah blah. Well either your a **** mechanic or your ****ing with me. Pretty sure its the second one cuz this is pretty damn clear there’s something wrong. Its just getting worse by the day here worried that its causing even more issues not dealing with the problem.

any idea on what it could be?