I know the 5.9 was a beast and is one of the best motors Dodge ever put into a truck.

I want to hear from the people that have owned both and what the pros and cons are of both. I have looked for nice 5.9's and there are a few nice ones, but there is nothing like buying a new truck. I looked at a brand new 6.7 today and they are making some really good deals on new ones right now.

My biggest concern is the particle filter. I have heard you can't let the truck idle. I would prefer to buy new, but I don't want to buy a truck that is going to be problems.

Any comments are appriciated.

Thanks

 

I've got a 04 5.9 and have loved it. The 6.7 is a good motor but with the dpf on it you don't get the gas mileage the 5.9's do, but you can do a dpf delete kit on it and pull your mileage up. The 6.7's were designed to work their guts out. If you don't haul a lot and get your egt's up you won't burn all the gunk out of the dpf. A lot of people that use them as daily drivers without towing quite a bit are having this problem.

 

I have a 2009 quad cab short box six speed manual. I have 1900 miles on it and have made up to 21 with it. It has no mods and is bone stock. I would recommend getting 3.42 ratio. I rodeo a lot and know lots of people with the 6.7. They are better than everyone says they aren't. I let mine idle. The only thing is that you have to let her stretch her legs and take it and run it every now and then to burn that crap out of your DPF.

 

K, you made 21 on the trip computer or hand calculated?

 

20.9 hand calculated and 21.3 overhead.

 

If you got 20.9 on a stock 6.7, that's a record because they just won't do it.

Even trucks with the DPF, EGR, Cat deleted and a good tune have trouble hitting those numbers.

As far as the gear selection, the only options are 3.73 and 4.10.

Chrylser has an updated flash on the 6.7 that allows them to idle up to 2.5 hrs, so that's not an issue.

All in all, the 6.7 is a great motor, it's just handicapped by the damn emissions crap. Get rid of that garbage and it's an animal.

 

I just had the opportunity to discuss diesels with my local dealership's diesel machanic. I used to work as an asst. golf pro and the guy asked if I would hit a bucket or two of ***** with him to help him with his swing. I've played golf with and given lessons to both the sales and service mgrs. there but have been nursing a degenerate condition in my shoulder, so I can't swing for sh*t anymore, but agreed to watch him hit.

We had a good discussion of the 6.7 vs. the venerable old 5.9. This is basically his take:

In '07 Federal emissions changes required ALL manufacturers to add a particulate filter and a "regeneration" function that requires more fuel to run the engine. So NO current diesel will get the fuel economy of the "older" ones.
Becuase of this, and even with the latest PCM updates that make idling better, you should NEVER allow your diesel to sit and idle for long periods of time. You need high exhaust temps to burn the particulate out of the filter. If you arent running the truck at higher rpms to keep the heat up, these newer PCM updates will have the PCM add fuel to the exhaust to do it for you. The problem that creates is that it's putting the fuel in the cylinder on the exhaust stroke. This means that a good portion of this fuel will get by the rings and cause the crankcase oil level to rise. This is not generally a huge problem if its not excessive or if you do not idle for too long.
If the oil is changed at Cummins recommended 5k, with about 600hrs of run time, its guaranteed that you've been through more regen's than a guy who changed his oil at 5k and 200hrs. You will have had more fuel in your crankcase and thus have dilluted your oil, potentially causing the engine to consume more fuel through the breather system. This will over time cause the engine to melt pistons.
Also, because of much tighter tolerances within the fuel system, the running of cheap fuel, off road fuel, bio-diesel, etc, will cause damage to your injection pump and injectors.
Over-all, if I could get my hands on a fairly cherry 5.9, I'd jump on it...

 

3.42 is available on the manual trans trucks, or it was last year anyway.

 

Yes, the 3.42 is available because I have it. And yes, I have made that kind of mileage. I have checked it three times. I was very surprised myself. It was at 65 mph, and there is a significant difference at 75 mph.

 

Ahh, you are correct. Never noticed the 3.42 option on them.

If you're getting 20.9 out of that motor, you need to share some of your secrets with the group because that is 4 - 8 MPG above the norm on most 6.7 trucks.