Ohioplower

Is there anything bad about these motors and the 03-early 04 trucks? I heard they get better fuel mileage than the newer ones so im considering one. Are there still issues with the lift pump and injection pump on these like the 98-02 24 valves? Should I look into 05's because the in tank lift pump? On the 04 trucks are you able to tell if it has the 305/555 or the 325/600 by looking at the vin #? Thanks

Mighty Goat

if you buy one, look at the fuel bowl first. If you can't see the lift pump on the back of it, you're good. The OEM mod has already been done. And to differentiate between the 04 and 04.5 I'd read the white sticker on the driver side of the engine head. It'll tell you which engine it is. There are ton's of threads on here about this. Do a search it's all on here.

Different ECM. More agressive stock tune on the 04.5.
Diff. injectors, stronger and one extra injection event on the 04.5 for better emmisions.
Diff. valves that flow a bit better.
4" exhaust elbow on the 04.5 for a full 4" turbo back on the 04.5
03/04's on have a 3.5" elbow, and it doesn't turn to 4" untill after the axle or so, Can't remember really, I just cut mine off from the muffler back untill I built my stacks and got the bigger elbow.

rip 112

Lift pump is the weak link, $500 bucks and solved. I love my 04, have had no major issues.

MikeyB

The 555 is very reliable if taken care of. Mine has been in the shop once in the 5 years for a blown hydroboost line.

As stated above the lift pump is a weak link, and valve seats. Excessive EGTs will drop the seats.

MikeyB

Z06-LITE

I have had my 2004 since November '03. Absolutely no problems so far. I have only been to the dealer to get my speedo recalibrated after installing the 22'5's. My truck is totally stock mechanically and I plan to keep it that way. I get good mileage and it has enough power for me.

johnr9q

I totaled my 99 and am looking to upgrade into the 3rd Gen. Based on the info in this thread, looks like for fuel economy considerations I should stick with the 03 or early 04? Is the 305/555 motor the only one offered in the 03 to early 04? Did the the later 04's have a different motor that I should avoid?

HotRodK

This is good info, seeing as I just bought an '04.. Keep it coming guys!

Slice

my 04 gets 21 mpg combo and 23 on highway. see signature for what on it.. and 75xxx no troubles..

Hounddog

In early 03 there was also 235 and 250 h.p. engines.Check tag on valve cover for H.P. and torque ratings.

dodgecbr600rr

good solid truck realy nice with the six speed. and great mpg

johnr9q

What is a 305/555 refer to?

MikeyB

305hp/555 tq. Cummins HO engine from 2003-2004.

MikeyB

Hounddog

305 horse power and 555 foot lbs of torque

ScottH

I had an 06 4x4 and now have an 03 2wd LongBed and absolutely love it....Around town Im getting 20mpg and freeway Im hovering around 22 or better......my 06 never got above 16mpg.(granted it was a 4x4).....my 03 has 135k on it now and runs perfect......and yes i still have the stock lift pump with a spare in the glovebox......its about the only weak link.

Ohioplower

I drove and 05 today and it was sweet. Should I look into a 05 instead of a 305/555 truck because of the lift pump issue? High Idle would be nice too. Are there any problems with cats and EGR valves being on these trucks? Is there that big of a difference in fuel economy between the 305/555 and the 325/610s? Thanks guys keep the replies coming