2000 Toyota tundra v8 4.7 rwd transmission

Hey Scotty I have been watching your videos for a while now and I have a question on my vehicle and I don't know if it's the transmission or the drive shaft bearings but I checked under my truck and the drive shaft bearing rubber was torn and the u joints seem fine but in one of your videos you said that if your vehicle had a bump when shifting gears the transmission is bad or could go bad and I don't know if I should buy a new transmission on it and when I do stop it did feel like someone behind me hit me but when I look behind there was no one there but anyways I bought off marketplace and it turned out as a good truck till the radiator blew and now the car is having all these random problems I just need your help on this and I'm new to cars and try to learn more about my vehicle and thanks man