i got ban till 2034 and this is my first time geting banded on forza4 why was it till 2034.
That would be a PERMANENT ban from the game because you attempted to sell a hacked car on the Auction House. The penalty is permanent expulsion from the Forza servers, hence a 20-year ban.
The Xbox LIVE Code of Conduct - even the back of your game box - warns about modifications to any games or their content by using external tools.
If you have further questions, feel free to contact Turn 10 at forzafb@microsoft.com. Neither bans nor the enforcement of the Code of Conduct are discussed on these forums.