Hi it makes a knocking sound when i'm driving under 30 mp...

Welcome to JustAnswer Mechanical Support! I amCustomerand I will be Investigating and Supporting your question today. I understand it can be really frustrating when your auto is not working an expected but don't worry as I am here to help! I may need further information, however, if required I will let you know! Sorry to hear your having issues with your vehicle I will try to assist you. Looking at the information you have provided it sounds like it could be a problem on the drive shafts or the prop shaft universal joints I would advise to get the drive shafts and prop shafts checked as it could be a worn universal joint or a fault with the center bearing support mounting. You can check them by chocking the vehicle so it cant roll and then with the emergency [brake](/topics-brake-toyota/) off check them by rotating them near the universal joints to check for any excessive play if the play is excessive it should be quite obvious also to check the bearing mounting you just need to check for any excessive up and down movement and check to see if the rubber is split and worn.