EAST TEXAS HOG DOGGERS FORUM

Alright need ur help again which cummins engine got better fuel milage the 5.9 or the 6.7 both with 3.73 rear end i believe and automatic with 4x4!!

5.9, not even a comparison. If it isnt broke dont fix it.

x2 the only thing with the 5.9's '03-'07 is the injectors tend to fail after about 100k-150k with the new low sulfer fuel and the 6.7 doesnt seem to have a problem with it. this is just my experiences and that of a cummins mechanic friend of mine. some people get lucky though.

My buddies 5.9 with a programmer and 38's got 24 I can only get 19 out of my 6.7 with the same extras and 34's. Injectors are a concern but you can get rebuilt injectors for bout $150 a peice and have em put in for about $600.

Is the 5.9 the straight 6 cummins? Also what programmer was used if you don't mind me asking?

I got 16 mpg wilth 2 4x4 5 speed duallys with the edge with attitude,(4.10) pipe, aftermarket air cleaner, one was a 98 5.9 and other was a 2001, wife has a 3.54 2 wd automatic and gets about 18 in her dually with edge pipe same extras.  My 6.7 4x4 (3.73) with complete delete and Smarty 67 ME gets about 20mpg. its single rear wheel and 6 speed manual and 5 inch pipe.  The 6.7 is a good truck after u delete it and update the clutch, 120k and no injectors so far, runs better than new after the egf pdf delete.  The clutch needs to be updated to the Southbend one about $1500 and I am nursing it another 10k miles.  If i turn up the Smarty beyond 30 hp it will slip, the dual mass is a junk set up and no good, its gone out beofre on me with stock motor.  The 5.9 i had all had the usouthbend update and no clutch prob after that install and 200k miles, also updated the input shaft on the nv4500 t the same time and the hydra slave cylinder, those southbend clutches are hell on pedal presure increases, they have the hyda update in mos clutch updates now sold, back then thye did  not tell u if will kill your leg in San Antone or Usston Texksus traffic!!!lol

What yr model 5.9?   03-05 5.9 fuel systems had a tendence to self contaminate causing inj. issues and eventual eng. failure,there was a recall to patch this problem, PM me the full 17 digit VIN ## and I can check it for you to see if and when the recall was done.     
 6.7 don't get the mpg the 5.9 does, the 07-09 had a lot of check eng light problems mostly programing issues. and when it is soccer mom'ed or grampaw'ed daily they get emission carbon build up and will need servicing.

I've got 3 5.9's in the driveway.   1999 24v 5 spd 4.10 Edge + airdog,  2002 24v 6spd 3.73 Edge, 2003 cr 6 spd  3.73 Diablo

I can get great mileage in all of them, or crappy mileage in all of them... all depends on the right foot.  All of them have programmers of some flavor, upgraded clutches, either southbend or valair, and all of them are worked.    Had to replace a vp44 in the 2002, but never an injector.  The 2003 CR has been through a couple injectors, but to be fair I was running an Edge pressure box on the highest setting for thousands of miles towing.

This past weekend I used the 99 dually 4x4 hooked to a 24x7 stock trailer with 12 steers and 3 horses and I averaged 13.8 mpg. The 2003 with the same load can get 2 mpg better doing the same job.

I don't have any real world numbers on a 6.7

2006

This post kinda makes me wonder if it was really the Edge pressure box that caused my problems in my 2003. I dumped an injector, flooded the crankcase with fuel, burned up the turbo... all while loaded with 200 or so square bales on a 32' trailer, 120 miles from home. It wasn't a fun day.

vin# 3d7mu48c23g857440

Is the 5.9 auto or standard shift?    The 5.9 had 545RFE auto, and the 6.7 has a 68RFE. The model ## for the trans's are a description and rating. 545= 5sp. with a 4.5 duty rating, (on a scale from 0-9),, 68= 6sp with a 8 duty rating,, RFE= rear wheel drive fully electronic.  The 545RFE's were prone to a lot of failures if work hard and not service regularly.  The 68RFE is a very good trans.

circle, you have an open steering linkage recall H46 most of them are just inspections with no work done, but some trucks got a light wieght streeing and we replace all the linkage with HD parts

Thanks,

Will they still honor that recall, given the truck has 220k miles and is 8 years old? 

on 03-05 there is an open air vent on top of the fuel tank that lets dirt/dust in the tank, Engineer's say it only take 2 tsp of dirt in the tank and a dirty fuel filter to to start the failure of the C3 Injection pump, before they figured that out we were putting engs. in farm trucks used in dust areas every 10k to 15k over and over in the same truck. had to do a very good job of cleaning the entire fuel system to stop repete repairs.

yeah it's still shows open on your vin ## Circle.

The 5.9 was a work horse. You can get great fuel mileage nd performance out of the 6.7 if you get the delete kit for it.

My buddy had a diablo pwoersport programmer, 38's, six inch lift and manual tranny in his 06. It was 3/4 ton 4x4. He also had a straight pipe. He has a newer 2010 model dually now and no DPF problems yet. I've had the delete kit, programmer, cold air intake, and egr delete for bout a month and my 6.7 drives better than it ever did. I got bout ten mph last time I went elk hunting in Colorado dragging a stock trailer with pack mules hopefully it will do better this year.

Chris I ran my 05 for about 70k with bully dog performance setting on it. performance is suposed to add timming only ??? I went through 2 sets of injectors before the truck made it to 150k and got traded off when the second set started going out. My mechanic said it is all from the new fuel not being oily enough to keep the injector pistons moving freely. He recodmends putting one quart of trans fluid in the fuel at each fill up. his service truck has 3xxk and no injector problems to date. ??? The injectors for the CR are not 150 bucks a piece as stated above, a set will run around 2k no matter how you slice it.

X2....all of our buddies that got newer trucks are always offering to buy our truck if we decide to get rid of it. I think that this one is a keeper.  ;D

     You are correct there, when i was still buying at the truck auction the last 2007 and 2006 were bringing thousands more than the 1th generation 6.7 trucks in 2007 and 2008, any last year 5.9 is worth more than the 1th 2 6.7's.  I bet its still the same way, lots of peeps quit dodge over the 6.7's, unless u have a deleted 6.7 you will go crazy for sure with the cel and limp homes.

I have a 06 5.9 auto 4x4 3500 srw on 35's and get around 20 mpg pushin close to 400 to the rw. Buddy has a 08 6.7 2500 short bed standard on 33's and is gettin around 13-14 with stock power.

5.9 all the way, I will never sell this thing. I'm saving for a 5.9 mega cab for a daily driver ( keep stock size tires) and keep mine as a Huntin/haulin truck. I have put mine to the test and am about to put a new front end under it after 115k mi and it has held up to damn near everything, never left me stranded on the road even if I have to drive home in 4x4 from snapping the 2 piece drive shaft :)

I've owned several and I liked the 5.9 better than the 6.7 but the trans was much nicer on the 6.7.  I had an 07 5.9 and then an 08 6.7.  The power was great on both trucks and they were both autos.  Stock I would get 17-18 out of the 07 and never got above 13.5 in the 08 and get as little as 10 towing.  I now drive a 97 12 Valve standard trans 4x4 and it is nice.  I get the power and driving around empty with an air filter and straight pipe I see 22-23mpg and towing around 17mpg.  I have ridden to Oklahoma twice in a 09 Mega Cab dually with a standard trans and we were pulling a trailer with horses etc and we usually see around 14mpg.

Ok thanks guys i appretiate ur time and opinions sounds luke the 5.9 is the way to go for a used cummins

My 06, 4x4 auto with the 5.9gives me 18 mpg at 177,500 miles. Only changed 2 injectors at 78,000 miles no problems since, except the dang a/c.