Asked this question on the 6.0 forum and overall opinion was to keep the 6.0 of course I was not surprised so would also like you 6.4 owners to comment.

2008 has 35,000 miles 4 door dually 4X4, XLT trim.
My truck is 2005, 58,000 miles 4 door dually 2 wheel drive, XLT.

 

alot is going to be with how you use the truck. I assume you tow with it (dually) so what gears do each have?

What is the basis for the trade? I see you have a 2wd now and the 2008 is a 4x4.

4x4 alone will help with stability and for those low traction moments with trailers.

IMHO the 6.4 is a good towing platform, your issue will be MPG's. They tend to not be as good as a 6.0. But the overall experience with towing and the higher ratings are in the 6.4 favor.

They don't blow headgaskets.

 

Remember one thing... A 4 wheel drive won't tow as much as a 2 wheel drive will... All other things being equal, I'd definitely go for the 6.4 I went from a 7.3 to a 6.4 and the difference in towing ability is amazing..

 

Any problems with the 6.0? If not, 23k miles isn't a big difference for a diesel. Do you need a 4by? Is it a screaming deal?
Don't get me wrong, having a 6.4 I wouldn't buy a 6.0, but 58k miles isn't a whole lot of miles. And no I have never driven a 6.0.
Just my 2cents.

 

if the 2008 is a job 1, i would keep your 6.0. if the 08 is a job 2 or 3 then i would go for it! i have 2008 f-250 xlt and love it. milage sucks but other than that its the best truck i have ever owned! i have had 5 diesels (7.3,6.0.cummins, and now a 6.4) and this is by far the best overall truck

 

I have a Job 1 , F350 Dually, CC 4x2, and its been fabulous..
check for radiators..

I steered away from the 6.0's cause of the nagging problems.

Sam

 

I have a Job 1 as well and have never had a problem besides one radiator. I'm pretty sure 09's and 10's are also having radiator issues, so this is not a Job 1 issue for sure.

I always hear "stay away from the job 1's" but there's not much difference between a job 1 and job 2/3. There was a range of VINs that suffered from an injector issue. I would stay away from those VINs. Other than that, there was a bracket added to the fuel tank (recall), a bracket in the seat, and a venturi-T mod done to mine (before I even bought it, NEW). None of these seem like they would effect the reliability of my truck compared to a Job 2 or 3.

I'm not sure when the new EGR style started, but at some point they switched from a coolant cooled EGR cooler to one that doesn't use coolant.

Job 1's computer software & TCM can be upgraded to the latest and greatest flash in a matter of minutes, so I really fail to see the reason to avoid Job 1's. Unless you really want TPMS sensors.

Job 1's do have a different Transmission Control Module as well as a different filtering method for the transmission, but neither of these have been proven to be better or worse than the Job 2/3. In fact the new 2011 6-speed uses a similar external transmission filter and a screened filter inside the transmission just like the 08 Job 1's did.... food for thought. Ford said they did this to avoid the single restrictive transmission filter from starving the transmission of fluid under high stress situations.

 

do they have TPMS for Duallys? I'd love to have that if it displayed the pressure, and not an idiot warning light..

I love this on my Suburban. (not a dually of course!)
helped highlight a screw in the tire before the light would have gone off.

Sam

 

I have never driven a 6.0.

I can tell you all about the 6.4 though. Great experience for me. I have a Job 1, only issue is the radiators.

I don't have a tuner on mine but I would encourage you to look into the Spartan CAT/DPF delete and tune package. For around $3000 you can add a lot of power and hopefully some MPG to get closer to what you are used to with your 6.0.

With the 6.4 you can expect a very quiet motor, smoooooth power, no soot. (I always hated washing my trailers and camper every week or so 'cause the passenger side would be black from the Duramax I used to drive.)

 

Depends on what you want out of the new truck.

I drove a 6.0 last weekend for the first time, and I was impressed by how well it did. We were dragging 11,000 lbs up a 15% grade and trying to see how fast it would go. At WOT it revved higher than my 6.4 did and came very close to the speeds my 6.4 was able to attain.

Down lower in the RPM range the 6.4 has a noticeable advantage which should make highway cruising easier with something heavy behind you.

I monitored temps with my scangauge both with my '08 and the '06 6.0 I drove, and the 6.0 had a considerably harder time staying cool under an extreme load. Each time up the hill the 6.0 engaged it's cooling fan as it hit 225 degrees, while my '08 stayed below 220 and never had to engage the fan. Might have something to do with the larger water pump, but I'm not sure. The tranny cooling seemed to behave identical.

I LOVE my 6.4! It's smooth, quiet, and powerful!

 

That is a difficult question to answer. I had a 2006 6.0, and traded it in for a 2009 6.4. The only thing I miss about the 6.0 was the sound of the exhaust. Other than that, the 6.4 and everything around it is better than my 6.0 was. My 6.0 spent about 2 months in the shop over the course of the 3 years I owned it. (5 injectors, 1 turbo, 1 oil cooler, 1 egr valve) and a few other things in there. On the way to the dealer to trade it in, it died on the side of the road. Luckily I was able to restart it and drop that headache off and get good trade in value for it. I now have 27K miles on my 6.4 with zero issues(knock on wood).
Back to your question, I can't really answer it because there are too many variables. However, if both trucks were sitting next to each other brand spanking new... hands down I would take a 6.4. But then again, I may even wait and see what the 6.7 has up its sleeves. I have a feeling the 6.7 will be king!