Being upside down is where you owe more than you get for trade in on a vehicle and you roll the negative amount into the new car lown.fastcrazyhurt said:what does upside down trade mean? i want to trade but have to get my truck paid off. what are the difference between 2008 and 2008.5? i have till jan. 2nd for the deals to come to an end so i could try selling for a couple weeks but then there maybe no more 2008s left.