On the edge of retiring, and looking to trailer a bit.
Looking at used 5th wheels and used trucks.

Don't want to break the bank, as I am not sure how much we will take to this new adventure.

The Dodge Cummin is just too much, unless it has a ton of mileage on it.
I don't like the truck style itself anyway, seems cheap, great motor, bad cab.

Chevy just doesn't feel right.

I like the Ford the best I guess.
The old 7.4 is suppose to be great, I've yet to drive one.
I have driven the 6.0 and the 6.4.

The 6.0 is nice, but has some big issues if tricked/chipped out, and not maintained, or upgraded.

The 6.4 is awesome..... the power is amazing, quick too, but it had some
issues too, if not maintained properly.

Not sure I even need a diesel, but used trucks don't differ all that much resale wise, between gas and diesel, with the latter being way better on fuel consumption when towing.

The cost of repairs scares me too.  

Anybody pulling a trailer that can advise me or lend some insight?

"Chevy just does not feel right"?

Back in 2010, I sold both my aging 1992 Chevy one ton truck (454 big block gas engine) and my 1998 Ford (5.4 Triton engine). I wanted to by a new truck, and decided to test drive a Chevy Silverado 3/4 ton, a Ford 250, and the Dodge Ram 3/4 ton, all with diesel engines. I was looking at mid-range priced trucks (for the trim and options), quad cab, short bed, and 4 WD.

The Ford had the best interior, but the Chevy (Duramax engine) had the best handling and the best performance, even though the Ford had more power (both HP and torque) on paper. I liked the Ram, but I  was wary of its reliability, or potential lack of.

I bought the Chevy (2011 model), and it has 70,000 miles now. Only trouble has been two glow plugs failing, and this was fixed under warranty. I only knew of the failure because of the engine warning light on the dashboard. I love the Duramax engine and the Allison transmission. My overall mileage over 70,000 miles, including regular towing, has been 16.7 mpg. The only thing I don't like about the truck is the lack of a Diesel Exhaust Fluid gauge. There is a text warning on the dashboard when you get within 1000 miles of empty, and it's not very reliable. Last time I saw the warning, it was at 769 miles, and within 200 miles it was indicating 149 miles left to empty! If you let the DEF level get too low, you will be limited to 55 mph, then 4 mph. The Ford has only a warning light, and the Ram is the only one with a DEF gauge.

Here in Colorado, any diesel truck will have a higher asking price than the equivalent gas engined truck. Difficult here to sell a 2 WD truck, so prices will be lower for those.

You don't mention your budget... Where I live, a truck like mine is now worth $30,000 at best.

Btw, most stuff you find on the internet is negative about any given motor, as people most often only post to whine  

A 2008 Ford 6.4 will not have the "pee injection" (LOL), only the DPF and EGR.  Yes, some owners delete them, thus gaining better mpg and more power. There are some possible technical problems doing so, including failing pollution control tests, and a possible $10,000 fine if the authorities catch you! The EGR system on this engine is a known source of problems though.

Like Justin wrote, if I were buying a used diesel truck, I would have a diesel mechanic do a thorough check on it.  Parts for diesel engines tend to be expensive.

FYI, check here:  https://www.littlepowershop.com/6-4-powerstroke-common-problems-issues-and-fi...

Ray , how much you thinking on haling ?

Seems like you might be more concerned about the transmission ... all the modern diesel motors are good .   Some are not as fuel efficient as others ...