Wanted to see what kind of mileage other 2500 Megacab 4X4 autos were getting. I have 3.73's. I'm getting an average of 13. Love the truck but wish the mileage was a little better. It's my first diesel, what kind of improvements can I look for when it breaks in?

 

There's a TON of posts/threads about this. Do a search on the site and you'll have more varying accounts of mileage than you know what to do with.

That said, the general consensus is that the engine is broken in around 20K miles or so, give or take a few thousand depending on how hard you work it. With 29K on mine (see signature - and you should fill out yours too), I see:

15-16 all city driving
16-17 mainly city / some highway driving
18-19 mainly highway driving (under 75)
16-17 mainly highway driving (75 or over)

There doesn't seem to be a lot of mileage difference between the 48RE and NV5600 trannies. The mileage from the new G56 manual is a little bit lower.

 

I've read many but wanted a better comparison with other Megacabs.

 

drakeslayer, I also have a Mega Cab CTD with a auto 3.73. When I first bought the truck in February, I was getting 11.4 mpg. Mileage has been slowly going up, to a point where I am now averaging around 14.5. I am not sure how much I picked-up going off of winter diesel........so maybe I increased 2 MPG in 3500 miles.
A lot of people do say that you need 15 to 20K to get peak mileage. I don't know why it would take so long, but apparently it does. I have a brother with a Quad Cab CTD and he is now getting 17 mpg (with 20k miles) vs. 13 mpg when new.

 

I have 1200mi on mine and I'm getting 18.4 had calculated. The overhead reports about 2mpg high.

 

Almost identical to what I am getting with the 3:73's and 48re. Getting better quickly it seems... which is nice. If I don't see much improvement over the 14.7 average I am getting now after about 8kmi or so, I may look into the flash for milage. Until then I am not jumping to conclusions.

Note: 6spd drivers tend to better on mileage, so don't be disheartened when you see them posting bigger numbers. They short shift and keep the engine out of the turbo.... especially beneficial around town where the auto gets to be pigish.

 

That's what I get...

The mileage is better with the NV5600, but not with the G56, at least at highway speeds. The G56 runs lower gears which cause higher RPM's at highway speeds.

 

If you search for my posts on the subject they are all accurate.

I get an average of around 14.

I have gotten as high as 16 on all highway kepping rpm's below 2000.


If I am towing my open car trailer with my car on it, my mileage is around 13mpg.

I needed a new truck and fell for the diesel bs that everyone gets 20+ mpg towing a million pounds into a 50mph headwind.


Now I know the truth.

 

Do you all think the manuals turn in a little better mileage because they are always "locked". Meaning, even though a G56 is a little lower geared it is directly linked to the engine, and there is no wasted slippage. Just wondering if that could be part of the reason. I constantly see on here and other sites, the manuals always average better than the autos. Not trying to get into which is better and I know the TC locks "almost" all the time, but there are still alot of times it will unlock and need more peddle, than say a manual, that just stays in gear and puts the power down. Scotty

 

The '03s get better mileage in all configurations as they are 4 gram NOX engines vs. the 04.5 and later at 2.5 NOX.

I got 20 MPG over 1600 miles on a trip to New Orleans to srtip out houses several wkks ago, and get 13.5 towing a 10K 5-er at 68 MPH on the Interstate.

John C

 

An automatic transmission is still a fluid drive and although they are getting closer to flywheel speed = 100% input transmission shaft speed, they are not there yet. With a manual what the flywheel is turning the input shaft is turning unless the clutch is slipping. There are probably a few less mechanical losses with the manual so hence they are slightly more efficient if they are driven properly. Greater efficiency is greater mileage.

L8R,..............dogger

 

Well, it used to be close to true... The craptastic gas mileage didn't happen until 06. Also for the sake of the thread I don't think quadcab/megacab would be a huge difference in MPG.

 

Mine has been steady at 13.5 or so. Mostly around town. My first pull this weekend with a 7000 lb. travel trailer in the mountains of AZ. We'll see how she does.

 

With the advent of the lockup converter you had better have 100% lockup or your lockup clutch and transmission will be toast in a few days of driving this way!! The OD in the auto is "taller" than in the G56 so you will get better highway mileage with the auto. The NV5600 is a has been in the Dodge.

 

WOW, somebody finally understands how a torque converter works...