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Old 09-16-2015, 10:36 AM   #1
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5.9L verses 6.7L inquiry

I am looking to buy a Ram 3500 Dually...... The tow limits are close on each....There are just so many more of the 5.9L to choose from.... Which is the better engine... I know the gear ratio has alot to do with the towing... however, it seems there are more of the 3.73:1 than there are the 4.10:1...... will i be ok with the 5.9L/3.73:1 as long as i am within or close to being within the limits.....
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Old 09-16-2015, 05:10 PM   #2
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Location: Powell River, B.C.
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6.7l is the newer version , of the 5.9.
5.9 was produced for 15+ years the 6.7 for the last 6 years or so. Retired from Dodge in 2007 and haven't really kept track.
When Dodge used Dana rear axles the 3:54 & 4:10 options were common.
With the switch to American axles in 2003 the optional ratios became less common, with the switch from the 4 speed automatic to 5 & 6 speed automatics and the engines increased torque numbers the options became even less necessary.
So you have to look at the whole driveline to figure it all out.
4spd automatic 5.9 with a 3:73 ratio , won't do as well as one with a 5 spd. auto and I don't know if the 5.9 ever got hooked to a 6 speed or if that was a 6.7 thing.
What years of truck are you looking at ?
99DSDP 3884, Freightliner, XC, CAT 3126B, 300 HP /ALLISON 3060
2000 Caravan toad, Remco & Blue Ox.
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Old 09-16-2015, 05:19 PM   #3
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Workhorse Chassis Owner
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Location: Byhalia, MS
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Retired from Dodge in 2007 and haven't really kept track.

So the 2007 early retirement package got you too?
2005 Newmar Kountry Star Gas 3742, Workhorse W24, 8.1L/Allison 5-spd
2017 Grand Cherokee or 2017 Harley Ultra in tow
JT, Em & the boys, Kong & Baxter (rescued grey tabbies)
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Old 09-17-2015, 08:45 AM   #4
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Location: Palmer Ak
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While not dually truck, I have an older 1994 2500 4x4 with a 5.9 that has over 235000 miles on it. The engine has been good and this truck has worked since day one. The engine has been 'tweaked' and now has over 275 hp. My other truck is a 2007.5 with the 6.7 engine that has over 165000 miles on it. Once it was out of warranty, the engine was 'tweaked' and now has over 450hp. This truck has also has worked since day one, but not as much the last few years, now that I am retired. The newer truck has lots of power, good MPG(20-23) and for me, no issues.
2009 38' Diplomat
CSM- retired, wife as co-pilot
Reka & Ali providing security (our 2 labs)
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Old 09-17-2015, 01:38 PM   #5
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I've had both engines, the 5.9 in a 2003 3/4 ton and the 6.7 in a 2010 one ton. They are both good solid work horses and towed the fifth wheel without any issues. The only difference I could tell was the 5.9 got about twice the fuel economy than the 6.7. Roughly 28mpg versus 14 normal driving, and yes these are real numbers. When I towed the same 5th wheel the fuel economy was 17 versus 13. Just my thoughts
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Old 09-17-2015, 04:54 PM   #6
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Funny that you say that because an uncle of a student of mine said the same thing as far as the 6.7 using a lot more fuel.
Martin Picke'
1998 Rexhall Anthem 34' DP, Cummins ISB, Allison 6 speed, Spartan Chassis, 300 watts solar.
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