I have a 2004.5 RAM with the 5.9L and the 4 speed automatic. I tow a 10,000# trailer for 18,000# combined. I find the transmission has awkward ratios at 55-60 MPH:At 55MPH - In drive, 1,500 RPM, Exhaust gas temperature in the 800'sAt 55 MPH - in Tow/Haul, 2,200 RPM, EGT in the 600'sAt 60 MPH - In drive, 1,700 RPM, Exhaust gas temperature in the 800'sAt 60 MPH - In Tow/Haul, 2,400 RPM, EGT in the 600'sWhat gear should I be driving in while towing at these speeds? It seems like it is lugging when in OD. I am thinking in terms of engine longevity, transmission longevity, fuel economy. The truck is perfectly content at 65 MPH in OD.

Towing keep speed high enough to allow the engine to spin around 1900 RPM

I would go with 60 in OD. 800 pre turbo isn't too bad.The thing I disliked about my 01 the most was the gap between 3rd and OD is too big. I switched to 4:10 gears which really helped but it was either cruising nicely in 4th or screaming in 3rd.The thing I like most about the 6.7 isn't the engine, it's the 6 speed transmission.

I tow with a 1996 Ford diesel with a 3.55 axle and have about exactly the same rpm vs speed ratio as your Dodge, and with about identical egts at those speeds. For the past 20 years I've been towing in overdrive at the 55 to 60 mph range and have experienced no mechanical problems with either the engine nor the auto tranny.Of course, when I get in the hills I shift it out of overdrive into third when the tranny starts "hunting," which is what Ford recommends. On long mountain grades, the gear I select is determined by my EGTs.

What RPM is peak torque? Probably around 1,900 or so. That's where you should be running it.The worst thing about those trucks was the 4 speed automatic.

^That. Not enough gears, but 6-800 deg egts are super low if pre turbo. That seems like post turbo temps. Can't imagine 600deg pre turbo pulling 10k even on a flat road. However, IMO I like my 5.9 running close to 2krpms or over when towing. Lower rpms makes my pre turbo egts go up quite a bit, but I'm adding extra fuel.

When is my Cummins the happiest? | Good Sam Community

Airstreamer67
Explorer
Nov 06, 2016
I tow with a 1996 Ford diesel with a 3.55 axle and have about exactly the same rpm vs speed ratio as your Dodge, and with about identical egts at those speeds.

For the past 20 years I've been towing in overdrive at the 55 to 60 mph range and have experienced no mechanical problems with either the engine nor the auto tranny.

Of course, when I get in the hills I shift it out of overdrive into third when the tranny starts "hunting," which is what Ford recommends. On long mountain grades, the gear I select is determined by my EGTs.
wilber1
Explorer
Nov 06, 2016
I would go with 60 in OD. 800 pre turbo isn't too bad.

The thing I disliked about my 01 the most was the gap between 3rd and OD is too big. I switched to 4:10 gears which really helped but it was either cruising nicely in 4th or screaming in 3rd.

The thing I like most about the 6.7 isn't the engine, it's the 6 speed transmission.
donn0128
Explorer II
Nov 06, 2016
Towing keep speed high enough to allow the engine to spin around 1900 RPM

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