[joepajamas]

I have been looking at getting a newer truck. I would like to have this truck for the next 10 years or so. With fuel prices the way they are I would like the darn thing to actually get 20mpg freeway. The trucks I have been looking at are shortbed extended cab models in the 2500HD series. Will these actually get 20mpg. If I spend $25k and the dam thing gets 16mpg I am going to be pissed because then I would have been better off just buying a gas motor. I really like the solid front axel, and the way the 6 speed shifts and feels, it seems to be at 1600rpm-1700rpm on the freeway at 65mph, which seems like it would yield good mileage. With the six speed, one might be able to put on larger tires without changing ring and pinions.

I thought about some of the 2000-2002 models, but after driving the newer generation cummins, it seems the quieter motor might be nice.

Does the 2003-2007 third gen cummins motor yield the best mileage of the 5.9 series?

Any thoughts on this matter appreciated.

 

[decoy]

I get 20 mpg on my 04 2500, but I pay $.50 more per gal. than reg.gas

 

[srchn4salmon]

Yup, its all the same, less gas mileage with a gas motor but more expensive for diesel. Diesel motors are supposed to last a lot longer though.

 

[Hunter P]

I have been looking at getting a newer truck. I would like to have this truck for the next 10 years or so. With fuel prices the way they are I would like the darn thing to actually get 20mpg freeway. The trucks I have been looking at are shortbed extended cab models in the 2500HD series. Will these actually get 20mpg. If I spend $25k and the dam thing gets 16mpg I am going to be pissed because then I would have been better off just buying a gas motor. I really like the solid front axel, and the way the 6 speed shifts and feels, it seems to be at 1600rpm-1700rpm on the freeway at 65mph, which seems like it would yield good mileage. With the six speed, one might be able to put on larger tires without changing ring and pinions.

I thought about some of the 2000-2002 models, but after driving the newer generation cummins, it seems the quieter motor might be nice.

Does the 2003-2007 third gen cummins motor yield the best mileage of the 5.9 series?

Any thoughts on this matter appreciated.

Basically,the newer the Ram,the worse the mileage will be. The 1st gen 12valves get the best. The second gen 12valves,then second gen 24 valves. Finally the 3rd gen 24valves. The reason the 3rd gen is in last place is because of the way fuel is injected. The early 3rd gen have 3 injection events,and newer have 5 injection events. Having more injection events makes the Cummins mucho quieter,but less fuel effiecient.

Going to bigger tires will also kill some fuel mileage. Yes bigger tires will decrease the RPMS some,but bigger tires have more rolling resistance. Aggresive tires also have more rolling resistance. The 3rd gen Rams can easily fit 33s stock. 35s with a 2" front leveling kit. 37s with a 4" lift and 38s or more with a 6" lift. My brothers Z-71 needed 6" of lift to fit 35s.

The Rams don't have super strong front ends though.. They have enough problems with ball joints,wheel bearings,etc going out without adding big tires. I want 35s in the worst way,but between towing a fifth wheel and wearing out the front suspension quicker I'll stick with 285s (33s).

My '07 5.9 4x4 with the 6spd manual gets about 19mpg at 60,18 at 65,and 17 at 70. Much past 70 and the mpg goes in the crapper really quick. Thats hand calculated and factoring in the taller tires.

If you want 20mpg,I'd find a 2003-2004 with a manual tranny,go easy on the big aggressive tires,and you MIGHT average 20 on the freeway.

Finally,you won't get 20mpg with a gas engine,unless its a 1/2 ton with a small block engine. A 3/4 ton with a small block (6.0 Vortec,5.4 Triton,or 5.7 Hemi) WILL not get you 20. You probably won't even average 15-16.

 

[timboy2]

I have the 07 Dodge Diesel and love this truck. Last weekend I got 21.5 mph coming home from Lake Chelan. When you go over 70 mph the mileage begins to drop off quickly. I have the automatic and only 4,000 miles on the truck. The manual says that the best power and mileage will be when it is broken in at 20,000 miles. I pulled my 26 foot Sea Ray home from the marina last week and the truck barely even knew it was there. Did I mention that I love this truck?

 

[BIG GUY]

I have the 07 Dodge Diesel and love this truck. Last weekend I got 21.5 mph coming home from Lake Chelan.

21.5 mph isn't that kinda slow.. :mrgreen: lol

 

[NR Stu]

I have an '06 2500 Quad Cab, Long bed 4x4 with 5.9 Cummins and automatic transmission. It has about 12,000 miles on it. I've seen 20 mpg on a couple of long hiway trips, but I average about 17-19 mpg. Pretty much the same as others have noted - keep it under 70. Mine gets the best mileage with the cruise control on and set about 65. I didn't buy mine for mileage; I bought it for towing. It tows my 7200 lb. boat very, very well.

 

[Chasin' Tail]

Buddy of mine has a 05' 2500 4x4 Cummins 6 speed. He added 35" BFG's to it.
Then we hit the Truck show and he added the Magnaflow exhaust and a SuperChips programmer.
He gets 20-23mpg on the highway staying at 60-65.

I have a 06' GMC Duramax 6 speed auto. Stock tires, but I also added the Superchip Programmer and Exhaust.
I get 20-22 on the Highway. 2 weeks ago I went to the Boatshow in Portland and got 22.6 mpg as a round trip. all Highway and set the cruise on 63..

Both of us noticed about a 2mpg gain from using the programmer vs stock. We didnt gain anything from just the exhaust.

We both document our mileage manually, and with the HUD in the trucks to verify the numbers..

 

[RiverTraveler]

I have the '07 5.9 Cummins and LOVE it. I get 21.5 mpg regularly on the freeway at around 60 - 65 mph. Like everyone else says over 70 mph and it drops down to about 18.5 mpg... The Solid front axle is great for off-road too! Tup:

I have the automatic so i can't speak to the 6 speed. However, the '03 - '07 (with some improvements in the '06 - '07) all have under sized transmissions if you're going to do a lot of towing... the new transmission in the '07 6.7L seems to be pretty sweet however I'm not sold on the emissions technoligy yet...

I bought mine at Dave Smith in Kellogg ID. The service was great and the price was 12K UNDER what the local dealers quoted me. Tup:

 

[SeaRanger21]

Finally,you won't get 20mpg with a gas engine,unless its a 1/2 ton with a small block engine. A 3/4 ton with a small block (6.0 Vortec,5.4 Triton,or 5.7 Hemi) WILL not get you 20. You probably won't even average 15-16.

2004 Dodge 3/4 ton 4 door short box w/5.7 Hemi I'm getting 17 around town upper 19 to low 20 freeway with good gas and a light foot, crappy gas seems to really have an effect on the mileage.

 

[Hunter P]

I have the automatic so i can't speak to the 6 speed. However, the '03 - '07 (with some improvements in the '06 - '07) all have under sized transmissions if you're going to do a lot of towing... the new transmission in the '07 6.7L seems to be pretty sweet however I'm not sold on the emissions technoligy yet...

I quote]

The 48RE is hardly undersized (whatever that means),its track record is just as good as the mighty Allison. The 47RE did have some issues with longevity.

The 68RE thats behind the 6.7 is basically the 48RE with 2 more gears. If the 48RE had issues (it doesn't) that would mean the 68RE would as well.

The 48RE is a great tranny up to about 450hp,which is about 125 more than stock. After that it needs to be beefed up.

 

[RiverTraveler]

The 48RE is hardly undersized (whatever that means),its track record is just as good as the mighty Allison. The 47RE did have some issues with longevity.

The 68RE thats behind the 6.7 is basically the 48RE with 2 more gears. If the 48RE had issues (it doesn't) that would mean the 68RE would as well.

The 48RE is a great tranny up to about 450hp,which is about 125 more than stock. After that it needs to be beefed up.

Hunter P, All valid points... I agree that it's a fine transmission if you're doing occasional towing. However, if you are a "HEAVY" tower like i said in my original post it may leave a little to be desired... One of my good friends is a Cummins mechanic and he sees quite a few back from the guys that tow a LOT.

That being said. Anyone who tow's a lot will need to make upgrades to their transmission...

The Dodge is still the best tow truck on the market IMHO... That's why i bought one! Tup:

 

[Tiderunner]

I have a 2006 Megacab, I love it. I get 20-21 mpg all the time. Plus, 15 mpg towing my seasport

 

[joepajamas]

I test drove a 2004 yesterday in Tacoma, at Dodge of Tacoma. The truck was blue with a matching canopy extended cab shortbed. The fellow that traded it in lived near Gig Harbor, and that motor was all rusty, pitted and what not. The diffentials were all pitted from salt, and the truck just had the nv5600 tranny replaced at 66ooo miles.

I forgot to mention it had aftermarket exhaust, intake, and was chipped. It felt to me like it had about 450hp. That thing hauled serious A$$. It felt like you could race cars, but might need to shift from second to fourth. The lot told me the sixth gear went out. I am guessing someone was towing stuff in sixth with that tuning chip turned up to the high power setting, and were probably lugging the snot out of sixth gear? That coupled with 35" tires, just tore that poor tranny up.

I have to admit, i really like these rigs.


Thanks for all the input.

I may be driving to Oregon this weekend to look at some.



ARE THE 1999-2002 Dodges the Gen II 24 valve motors?

 

[Hunter P]

I test drove a 2004 yesterday in Tacoma, at Dodge of Tacoma. The truck was blue with a matching canopy extended cab shortbed. The fellow that traded it in lived near Gig Harbor, and that motor was all rusty, pitted and what not. The diffentials were all pitted from salt, and the truck just had the nv5600 tranny replaced at 66ooo miles.

I forgot to mention it had aftermarket exhaust, intake, and was chipped. It felt to me like it had about 450hp. That thing hauled serious A$$. It felt like you could race cars, but might need to shift from second to fourth. The lot told me the sixth gear went out. I am guessing someone was towing stuff in sixth with that tuning chip turned up to the high power setting, and were probably lugging the snot out of sixth gear? That coupled with 35" tires, just tore that poor tranny up.

I have to admit, i really like these rigs.

Thanks for all the input.

I may be driving to Oregon this weekend to look at some.

ARE THE 1999-2002 Dodges the Gen II 24 valve motors?

Towing in 6th isn't a problem,I pull almost 11,000lbs in 6th without any problems. Pulling with big tires and lots of power IS hard on 6th gear,it is after all OD.

Does the truck have any aftermarket gauges? Namely a pyrometer. Running a chip without monitoring the EGTs is a sure fire way to burn a piston or cook a turbo.

Yes the Cummins is 24 valve from '98.5 on.

 

[timboy2]

I have the 07 Dodge Diesel and love this truck. Last weekend I got 21.5 mph coming home from Lake Chelan.

21.5 mph isn't that kinda slow.. :mrgreen: lol

It was snowing heavily, lots of traffic, and I was kinda scared. lol But the mpG's were great.

 

[joepajamas]

Truck didn't have gauges. What's pyrometer and EGT's? I may google them. I am guessing it has to do with heating up motor, or detonation type scenerio only in a diesel?

 

[Hunter P]

Truck didn't have gauges. What's pyrometer and EGT's? I may google them. I am guessing it has to do with heating up motor, or detonation type scenerio only in a diesel?

If the truck didn't have gauges,and had any kinds of mods done,I run,not walk away. A pyrometer measures the EGTs (exhaust gas temperatures). When the EGTs get too hot (very common on juiced trucks) bad things happen. You can melt a piston,or a turbo amongst other things. The fastest way to high EGTs is either lugging the engine or a chip/programmer. Lugging a diesel is when you either can't accelerate or gain RPMs when giving more throttle. Its pretty hard to lug a diesel with an auto,because if you give it more throttle and it won't accelerate,the transmission will down shift. With a manual you can run the rpms way down if you don't downshift. Running the rpms down and not downshifting makes a ton of heat. The EGts go up and if you either don't backoff the throttle or downshift you start melting things.

Thats where a pyrometer comes in. You can monitor the EGTs and back off when needed.

 

[joepajamas]

I have been staying away from any modded trucks. The add for this one didn't list that it had engine or exhaust mods. I wouldn't even have driven down there to look at it, if I had known it was modded. I basically found out it was modded when we started it, the exhaust sounded a bit different, then when i pulled out of the car lot and gun it, it went like a bat out of hell.

My logic has been stay away from modded rigs, and ones with fifth wheel hitches. The rig I drove had way too many issues with rust, pitting and mods for me to even seriously consider. I have been looking at ones with under 75k.

Thats good info to know about the lugging that can occur with manuals. You would think there would be some sort of EGT warning temp sensor set on a delay where gasses stay up for a certain amount of time the alarm would go off.
I have been trying to avoid automatics. I guess if there were 5 speeds available it might be ok, but I owned a 7.3 powerstroke e-350 van a few years back, and 4 speeds didn't seem like enough gears for a diesel. So I have been leaning toward the ones with the NV-5600. I love granny gear. Maybe I will started a stump pulling business when I get my truck. hehe.


Joe

 

[RiverTraveler]

If the truck didn't have gauges,and had any kinds of mods done,I run,not walk away. A pyrometer measures the EGTs (exhaust gas temperatures). When the EGTs get too hot (very common on juiced trucks) bad things happen. You can melt a piston,or a turbo amongst other things. The fastest way to high EGTs is either lugging the engine or a chip/programmer. Lugging a diesel is when you either can't accelerate or gain RPMs when giving more throttle. Its pretty hard to lug a diesel with an auto,because if you give it more throttle and it won't accelerate,the transmission will down shift. With a manual you can run the rpms way down if you don't downshift. Running the rpms down and not downshifting makes a ton of heat. The EGts go up and if you either don't backoff the throttle or downshift you start melting things.

Thats where a pyrometer comes in. You can monitor the EGTs and back off when needed.

Good advice! Tup: Any truck with a chip/programer or engine mods that doesn't have gages IS going to cause you trouble... a Transmission/Oil Temperature gauge isn't a bad idea either...