I have an 04.5 (auto) and have nothing bad at all to say about it!! Bought it new it now it has 62k on it. I believe if you look at the date of manufacture anything made in the 8th month of 04 or later should be what they call the cummins 600 (04.5). again great truck no issues. Mileage wise I get about 14 in town and anywhere from 18 20 mpg on the highway empty and 11 to 14 towing 28 ft 5th wheel. Hope this helps

 

How many miles do you have on your Mega Cab?

Won't the gas mileag get better with more miles.......

 

The '04s are different than the '04.5s.

The '04 with the 305/555 engine has the 48RE, no catalytic converter and no third injection event. They seem to get better mileage then the '04.5 model. And the 20 HP difference means nothing.

The '04 SO engine (in Ca.) has the cat, has 235 HP and does not have the HO upgrades like gallery cooled pistons. And it may have the 47RE and 10.5 inch differential. Still a great truck that responds very well to a Smarty.

The mileage of the SO and the HO should be the same as long as you are not using more than 235 HP.

As soon as the '04.5s came out people started complaining about mileage. Some guys seem to do well but there is no standardization on mileage claims. Trends mean more.

John

 

Gas mileage will never be good in a diesel because they only run on diesel fuel, not gas.

John

 

I have the 04 CA emission 235hp. It is an early 04 model made Oct 03 actually. It has 48re and 11.5 AAM Axle. The only difference, now of course, between it an the HO is the Smarty. Meaning Smarty leveled the playing field. The only real difference between SO and HO is the cat and ECM programming.

I have over 120,000 miles on it. Have replaced nothing yet due to failure. Everything in the sig-- like the LP for instance-- was by choice, not because I had to. I got about 19.5 mpg stock. Added Banks right off the bat and got additional 1 mpg. Added Smarty later and got another 1-1.5 mpg. I average between 21-23 mpg now. (This is with Banks OFF)

 

Sound like 03-04 HO is what I want. I have heard very good things about the mileage of these trucks.

I love my mega cab, but I am tired of letting it "break in" to get better mileage. I have finally come to the realization that these big trucks are never going to get the mileage of an economy car, and if they did it will still cost .40 more gallon to fill them up. Selling my truck which is ~$40k, and getting a $20k truck and a cheaper car will net me savings in the long run and that is what I am looking for. I don't need to drive the truck everyday, just when I tow. My mega is awesome and the best riding truck I have owned, but the mileage is not what I thought I was getting into. Listened to too many of these my CTD gets 100mpg threads I guess...

 

Yes, the '04.5s are great trucks but the cat and the extra injection event brings down the MPGs by 10-20% from what I can tell.

If mileage is what you're after be sure and get the 3.73 gear ratio. Also, the stock Michelins look whimpy but return great mileage at 75-80psi. That said, lately I've been averaging just under 20mpg with my BFG 285s. Got 21mpg on a trip last weekend that included lots of 65-80mph interstate. Used to do even better than that new with the stock Michelins and air dam (lost it the first winter). I get 11-12mpg pulling my 10k+ lbs. toy hauler at interstate speeds.

IMHO, the SO with 47RE is nothing to back away from- they seem to be the mileage king. On top of that, you should be able to get one $2-$3k less than a HO w/48RE. Use the difference to build your tranny if and when it goes. A built 47RE really isn't any weaker than a built 48RE, and both will fail eventually in stock form anyway.

 

Iv got an 03 with 111k miles and it runs like a champ. Like everyone has said the stock lift pump is a joke but installing an after market one is no problem. The 47re is a good trans and is not the same as the 2nd gen one. Id check the carfax report also before you buy, just a thought.

 

My 4X4 shift ****(electronic) went out at 105,000 miles, LP went out at 128,000 miles and my left front axle at 176,000 miles. I get about 23 MPG at 1800 RPM (65 MPH). I keep my tires at max pressure.

 

75,000 miles and zero problems.

 

111,111 miles and had a/c damper door, power steering, and tranny issues. Tranny issues have been my fault and I loved every minute of it! Get the 03-04 HO w/ a 48RE. I'd try to find a stock one(no mods). Then BOMB away!!! Good luck!
Whoops forgot about u-joints, those were my fault too

 

ok so dreging up this cuz im looking at going to tx and getting a 03 6-speed 4x4 with 163k, sounds like lift pump is the main think i got to worry about right? anything elce? its the HO 305.

 

04, 185,000 miles.......lift pump, rear axle seal, left front axle, electronic 4X4 control......thats what I've replaced.

 

I'm looking for a 3rd Gen too. What does everyone feel is the overall best year then from 2003-2005? Thanks Pete

 

I have an 04 555/305 and has never been in the dealer except once for a expensive oil change.(I will never do that again). It has 73000 and tows 10-11000 pounds about one third of the time.I wouldn't trade it for anything.
I use it for work everyday mileage is 19-20 unloaded.