It's the value of the new ones that most directly effects the value of the used ones. Like 94rt10ohio said, when they are giving rebates, incentives, discounts, etc. to the point where you can walk off the dealers lot with a $42k MSRP truck for $26-$28k, then how can you expect them to give you top dollar for a used one in trade.
Hell, the Diesel guys never really had this problem, but you watch, they'll be screaming next. For the first time I can remember, the local Dodge dealer is running ads in the Sunday paper for 2500 QCSB CTD 4x4's for $10k off MSRP.
Hell, when I bought mine in '04, I really wanted a diesel, but they'd knock off $8k on a 1500 Hemi 4x4 and I couldn't get them to knock off more than $2000 on a Diesel truck. That meant I'd be paying roughly $17k more for a truck that only MSRP'd for about $11k more, there was no way I was gonna foot that one...

 

Lets also not forget the market is flooded with these things, i see newer dodges EVERYWHERE i travel: supply and demand- the more there is of something the less its worth.

 

biggest part is the rebates and incentives that Chrysler offers... makes it tough to beat buying a new one instead of a used one. The only trucks that are doing well at the auto auctions are the unique ones like the Daytonas, Rumble Bees and such. The SRT's are doing poorly because of their basic limitations of being a real truck. But the other big contributor is of course the gas prices. I just leave mine parked in the garage and drive my '99 Buick Lesabre that gets 30mpg on the freeway... nothing like getting 500+ miles on 17 gallons of gas in a nice big comfortable car. Hell I havent even driven my Neon in about 2 months because of the ride and comfort of the Buick, its sad... it was my G-ma's car till she bought a new Buick and now I know why she loved the car so much and since it only has 34000 miles it still has a long life ahead of it(and best of all it was totally free to me).

 

I got caught up in the panic BS back in the 70's and traded-in a Lincoln Mark that I had done custom work on for a Mazda RX7; although I did like the Mazda I missed the Mark every day.
Think I would do a beater or a bicycle before I would give up the Ram and get screwed too.

 

Here's a "real time" update on trade in values: I traded my 2004 Quad Cab Hemi on Saturday for a 2008 Quad Cab Hemi. 93K on the old one. 2008 listed at 35K, got it for 23K (With vendor discount) but only got 9K in trade for the 2004.

I DON"T CARE THOUGH CUZ HEMI'S ROCK!!!!!!