I very recently purchased a used car from a dealership (the car was a
2005 in excellent condition with only 12,450 miles on the odometer) but
due to a change in circumstances I'm not going to be able to afford the
monthly payment. However, I do still need a car, albeit a cheap banger
that's going to last me three or four years at most (something for
three or four thousand bucks at the most).

I have hardly paid off anything on the 2005 yet. I no longer have cash
to put down (I didn't put  much down to begin with because I financed
with a Capitol One Blank Check) and yes, my loan is "upside-down",
although not by very much (the taxes and fees are what pushed the price
past blue book dealer value).

What I would like to do is trade in the 2005 and get a cheapo banger
instead from the dealer. The problem is going to be the difference
between what the dealer is going to give me on the trade in and what I
still owe on the car (and for the record, I have no choice but to
finance the cheapo car, that's the kind of situation I'm in). The
difference is going to be like 3000 bucks.

I don't know how this sort of thing works as I've never been in this
predicament before; is there any way the dealer would roll over the
amount I'd still owe in cash into my new (much lower) loan, for the
banger?

Any advice would be greatly appreciated.

-J.D.