I have a 2001 2500. I am looking to purchase a 2007-ish 2500 4x4.
What is the difference in engines? I see folks with same year/model as I do trying to sell there's and they always say something like "...has the desirable 5.9..." What makes the 2nd gen 5.9's (like mine), better or worse than the newer generation?

 

The 07' 5.9 didn't have a lot of the emissions crap the 6.7 did, but if you live in a rural area you can delete that crap.

 

Thanks! Follow-up:
1) Ref the 6.7, when did they start switching out the 5.9 for the 6.7?
2) I love the fuel economy of my 2001 (avg 19-20mpg). Is the MPG different with the 6.7?
3) Also, my '01 5.9 pulls great--how does the 6.7 compare?

Tks!

 

I used to have a 2001 5.9 w/ 6 speed manual, and It was a great pulling truck. I have a 09' 6.7 w/ 6 speed auto now. It pulls similar to the old truck, but I don't have to shift now. The 6.7 came out in January of 2007. As far as MPG, I got about 18.x MPG with the 2001. Now I'm getting around 17.x with the 2009, but it is a dually with an auto.

 

Yeah in 03 they went from the vp44 injection system to CP3 with common rail electronically fired injectors. Quieter, nice running trucks, but I don't think they got quite the mpg.

They had a 555 HO, and CA legal standard output. In 04.5, they came out with the 50 state 600, which has a cat where the HO did not, and doesn't seem to get the same Mpg.

When the 6.7 came out in early 07, there were a lot of threads about check engine light, issues with emission stuff, and poor mpg. On the plus side 6 speed auto replaced the 4 speed, though I've always run stick shifts.

 

Thanks Jeff--good/useful info to add to my search criteria!

 

2007 was the switch-over from 5.9 to 6.9. As mentioned before the early 6.9's were problematic where the 5.9 wasn't.

I got up to 24 mpg (best tank) or about 22 mpg average in my 04. Basically though, more power equals less mpg for the most part. The big difference in engines (still talking 5.9) was the high pressure common rail injection system. With a better turbo and more power.

The rest of the trucks themselves was a big leap forward in driveability and features along with softer ride and a higher gvwr. In my opinion anyway-- YMMV.

 

Jeff (or others),
"...In 04.5, they came out with the 50 state 600, which has a cat where the HO did not, and doesn't seem to get the same Mpg. ..."
QUESTION: I'm looking at a 2004 HO. What does "HO" mean? and "50 state 600", i don't comprende. And, how do you tell difference with 2004 and 2004.5 ?
Thanks! D

 

There should be a decal on the side of the rocker cover with that info, also maybe the build date might be useful too. Built after January of 04, and it prob a 04.5.

 

Ok...
Question: HO...assume that means "High Output"...but what does it REALLY mean? Higher than what?
Question: cat or HO... what's the difference (pos/neg?)
Question: "50 state 600" what does that mean?

 

They are torque and power specs.

The 2003 had a SO (Standard output) with a 47RE auto trans. Can't remember the exact numbers, but you lost around 50 ft-lb of torque. The 5 speeds were all HOs, but they were worried about the 47RE behind the bigger torque.

The 2003 HO is a 555tq/305hp engine with a 48RE trans, which is a better built trans internally.

I don't think there were any 2004 SOs, so it's pretty much gotta be a HO with the 48RE. someone correct me if I'm wrong.

In 2004, 1/2 they went to a different fueling scheme and made 600tq and 320hp or something. A bit more power, and a bit quieter due to an extra injection event at the cost of fuel economy. These are supposed to be the trucks to get. Simple and powerfull. I have the 2003HO and it's just fine as well.

Hope that helps

Chay

 

03 to 04.5 there were two choices in Cummins engine. Standard Output was 235 hp 460 ft/lbs while the High Output was 305 hp 555 ft/lbs if I recall correctly. Also in 03 the body style changed and American Axle and Machine axles were used instead of Danas.

Early in 03 the HO came only in stick shift New Venture 5600 transmission in non-CA emission states with 11.5" AAM axle. If you got an auto at first it was the SO and the 47RE with a 10.5" AAM rear axle I believe. Mid year the stronger 48RE came out, and a HO could be had in auto. I think all the Cummins pickups also went to the 11.5 AAM rear, in choice of 3.73 or 4.10 ratio.

After 04.5 was the 600 ft/lbs engine that apparently had a late injection event to keep the cat reaction going, and also the turbo got a 4" exit pipe, where it had been 3.5 inch from turbo to a resonator and 4" back from there. According to forums, this late injection event resulted in lower mpg, but met the tighter emission standard.


The engine from 04.5 through early 07 was called 600 because it was rated 325 hp and 600 ft lbs, but they later changed the claimed torque to 610. It was referred to as a 50 state engine because it was smog legal anywhere in the US, and was the only version of the Cummins sold in pickups during that time (no more high output or standard output).

Stick shifts also went from the discontinued NV5600 to the G56. They can be distinguished by the NV's iron case vs the G's alloy case. The G also uses a dual mass flywheel.

Engine output specs can be found on a tag on the side of the valve cover.

Hope this helps.

 

P.S. Early in 07 came the first 6.7 l engine, 650 ft lbs, 350 hp I think, if you got the 68RFE transmission, which is a 6 speed double overdrive automatic, considerably stronger than the 48re 4 speed auto it replaced. The engine also had a DPF diesel
Particulate filter. Stick shift trucks still got the G56 and the engine I think was derated to 610 ft lbs. The G56 is a smoother shiting transmission, but as I understand it, it won't tolerate aftermarket engine power increases as the old NV5600 would.

The engine had a variable vein turbo, which could restrict down to provide exhaust brake function without adding a Jake or Pacbrake. The 68rfe was compatible with exhaust braking, where the previous 4 speeds had to be modified. 5th and 6th are both overdrive ratios on the 68RFE. I drove one with a 4.10 axle, and it turned lower RPM at 70 than my 2006 with the 6 speed manual G56 and 3.73 axle.

There were various reports of quite poor mpg in these first 6.7's as well as check engine light and what not.

2013 I think it was another change, with selective catalyst reduction emission (SCR) becoming standard. Basically a 2nd special cat, with a urea solution (diesel exhaust fluid) used. Also another auto, the Aisin 6 speed, could be had in one tons. A super
Strong 6 speed double overdrive auto, which came with 385 hp,
850 ft/lbs rated engine.

IMHO if I were shopping and preferred used, I'd prefer a manual transmission 03-07 5.9. The autos of the era are ok and reliable if taken care of, but personally being only 4 speed would be a bit limiting if towing. Also the manual transmission can use an exhaust brake without modification.

If I wanted a newer truck, or really wanted an auto, I think I'd opt for one of the newer SCR equipped trucks (2013 and later). Folks seem to be reporting better MPG with them as opposed to earlier 6.7 engines. I think I would deal with the diesel exhaust fluid to get better fuel economy.

Just my opinion. Seems like every time there is a change to meet tighter emsissions, power ratings go up but MPG goes down and more complicated emission stuff goes on the engine.

 

One correction to the above... there were 3 engine ratings during 03-04.

HO was the triple nickel = 305 hp and 555 tq
SO was 250 hp and 460 tq
California emissions was 235hp and 460 tq


refer to my sig below

 

Interesting. I did not know that.