Assalamu alaikum wa rahmatullah, Ustadh is buying and selling cars at car auction in the west permissible? Or in the Muslims lands?

Yes, buying and selling by auction is permissible, where an item is offered and buyers raise the price until it goes to the highest bidder, and it is allowed in the West and in the Muslim lands alike. What matters is that the goods are lawful and actually owned by the seller, that the item and the price are clear so there is no gharar, and that the bidding is real. It becomes impermissible if someone bids only to drive the price up with no intention to buy (najsh), or the goods are unlawful, or the seller sells what he does not own or possess. What is also problematic is if they impose late fees for delayed payment, because that is riba.