al5608

Pulling a heavy load compared to a 5.9. If you were to compare two bone stock, identical trucks with auto trans, which one pulls better? I'm sure the 6.7 will pull better, a few extra HP and 6 speed auto, but, is it really that better than a 5.9? I have only seen one comparsion between a 5.9 and a 6,7 that a magazine did. I think it was Diesel Power Magazine. But they were not comparing two identical trucks. The 6.7 was bone stock, and the 5.9 was lifted with 35" tires. That's an unfair advantage to the 6.7. Who has owned both truck and can compair?

dodgestang

I've owned:
05 dually 5.9 auto
08 2500 6.7 6 speed auto
08 dually mega 6.7 6 speed manual

Stock the 6.7 2500 auto felt faster and towed easier than my 5.9 dually auto (once I added a weight distrobution hitch anyway). After I had added the box, the exhaust, and the intake to the 5.9 it was unstoppable and would go up the Appalachians faster than the 6.7 could. However, once I mod the 6.7 I expect that to change

Just as a side note...the autos 'feel' faster out of the gate than my stick...probably because I don't have a torque converter anymore but it was an interesting thing that I noticed.

yellowhemi

Once, when I had my 07 in for service, the dealer gave me a 6.7 as a loaner. Mine is a 2007 quad cab 4x4 auto
Theirs was a 2008 quad cab 4x4 auto
At the time, I had a Triple Dog programmer set on tow/economy so there was a small addition to my truck. Nothing else. I couldn't stand the 6.7, it seemed slow and my 5.9 felt like it could run rings around it. However, I loved the exhaust brake, it was very quiet too. Otherwise, same basic truck.

jerry007

bone stock it is a close race. I have 2003 2500 2wd with 4:10 gears. Then I have 2007.5 with 3:83 gears. Coming off the line is almost dead even. But torque of the 6.7 is a good bit more. Low end pulling , the 6.7 has thr 5.9 beat. The VGT turbo makes a huge difference.

Pirate

My sig shows the 2 trucks I have used. I have towed heavy with both using the same trailer and load. I'll take the 6.7 with the new 6 speed auto over the 5.9 with the 4 speed auto any day. My '99 was "lightly modded" only for towing purposes. The '07 is still stock and out pulls the "modded" '99. I really beleive the tranny has more to do with it than the 6.7 -vs- 5.9 but I don't have documented numbers to support my opinion. The EB also helps a whole lot but I had a PacBrake on the '99.

I use a 37' GN to move my Genie boom lifts and scissor lift to and from job sites. The trailer weighs in around 7200 lbs, the Genie boom lifts weigh in at 13k and 14k depending on which one I have loaded. The scissor lift weighs 4800 lbs and I can load it with 1 of the boom lifts. That makes for a total pulling weight of around 26k not counting the truck and other loaded tools.

In summary, I would not go back to a pre 6.7 for towing heavy.

BroncoHound

Actually, it's probably because your G56 equipped 6.7L is derated from the factory by 40ft. lbs. torque. The 68RFE 6.7L's are rated at 350hp/650trq. The G56 6.7L's are rated at 350hp/610trq and if you ask me that is STILL too much for the sissymerry clutch they put in these things from the factory. The 325hp/610trq series HPCR 5.9L is almost too much for the OEM LUK clutch in front of the G56, I can't for the life of me see the wisdom in Chrysler leaving the known weak point of the driveline unaltered while simultaneously upping the power output. I've got 50K on my '08 and my OEM clutch is barely hanging by a thread, and I am the anti-hotrodder.

cginwyo

My 2000 will outpull my 2009, and get better mileage.

randy.pratt

I had a 2005 2500 Quadcab 2 wheel drive with auto. I now have a 2008 2500 Megacab 4X4 with auto. I've had the same 28 foot toy hauler trailer behind both for 1000's of miles. The drivability of the '08 is way better. Where the '05 would downshift on a moderate hill, most times you had to play arround with some speed changes to get it back into the highest gear. The '08 typically is back in 6th as soon as you crest the hill (regardless of the tow / haul setting). Things I like about the '08: the ability to manually control the top gear with the switch on the shift lever, the exahaust brake is something you don't know you are missing until you have it (I can't imagine not having it now) and the 6 speed auto just seems to be more tuned to the whole package than the way the '05 drove. Things I miss about the '05: the turbo sound! The '08 is just quieter in every respect and you seldom hear the turbo, at least as compared to the '05. Fuel economy, granted I went from QC to MC and 2X4 to 4X4, and I haven't even passed 10K on the odometer of the '08 yet, but it looks like the '08 is going to get at least 20% less fuel economy than the '05. My '05 with about 40K miles was routinely getting 12 MPG, perhaps down to 9 MPG on a windy day / hilly road, pulling the said trailer. The '08 is getting never better than 10 MPG and down towards 7 MPG on that windy day / hilly road. At today's fuel prices, I'd take the '08 anytime over the '05 just because I like the power of the '08. Should diesel go back to $5/gallon, the memory of the '05 going a couple of miles further per gallon is going to tip the scales back to favoring it. I suspect some of the fuel economy difference is the fact that the '08 is so easy to push hard. I'll be in the passing lane going up a hill pulling a 10K trailer just because it can do it so easily. With the '05 I was more likely to back off some because it would drop down 2 gears and be running close to red line.

Bottom line, no surprises really: 08 vs 05 14% more engine displacement plus some Bluetec emission control = 20% less fuel economy (with a noticeable increase in power and improved drivability due to the 6 speed auto and exhaust brake).

tejas transport

The end of next year I will be getting a new truck. I am at 251,000 on my 06 right now. Its sad to say, but unless the 2010 are much improved in their ride, Im going with a 3500 Dmax. Ive had a 2001, 2004.5, and own a 2005 and a 2006 CTD. The newer chevy's are much improved and ride wonderfully.

gbsorenson

I have an 04 5.9 my Dad has an 09 6.7, both trucks are 2500 auto's and bone stock, no contest the 09 pulls much better. Mileage on the 09 has gotten better, started out at about 16, now after unplugging the EGR it's getting up to and sometimes just over 20. My 04 will consistently get over 20 so it is a little better on fuel. Love the 6 speed auto, that's likely a big part of the difference, and also really like the exhaust brake.