Concerned Towing

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Jul 9, 2007 | 10:10 PM

cfd312

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Concerned Towing

Hello all. I have a 2006 SD with a 6.0L and today was my first big pull with it. I bought a new 2007 PJ goose neck with a gvw of 20000lbs. I was loaded with a body from a fire truck going to a local body shop 45 miles away. Problem is the trans while in tow haul mode would not shift into what I am calling not overdrive. The rpm was in the 2600 to 2800 range and used a 1/4 tank of fuel.

Axle weights are front 4440 rear 5550 and trailer 9970 for a total of 19960. Wheel base is 142 and don't know the axle ratio but the door showed 3L. Can't quite remember if I am at the trucks GVWR for trailer towing. Can't find it in the owners manual. Road didn't have much of grade fairly level few hills. Trans temp never moved past half way but did hear the engine fan quite a bit. Temp today was mid 80's with lots of humidity. If anybody has questions just reply or email I am a little concerned because I was trying to start a part-time business. got all the DOT lic and State Lic and was ready to rock until this happened. I will also put this thread in the 6.0L cat. Thanks to all Aaron.

Jul 10, 2007 | 02:47 PM

Casey

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Until what happened? I don't understand what you're asking about. Everything looks normal from what you have posted. Is there a problem?

Jul 10, 2007 | 09:44 PM

cfd312

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Nope that is just it. I thought there was a problem. By the sound of it from th eother forum this is a common thing. Will have to deal with it until I can afford the new SD. F450. Thanks

Jul 11, 2007 | 09:04 AM

mitchntx

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Quote:

Originally Posted by cfd312

Problem is the trans while in tow haul mode would not shift into what I am calling not overdrive. The rpm was in the 2600 to 2800 range and used a 1/4 tank of fuel.

Not sure where you were hauling to and from, but ...

The trans will NOT shift into OD, while in Tow/Haul, till you reach 60mph ... period. Try it in Tow/Haul without a load ...

Once the boost starts climbing towards 20psi, it will shift out of OD very quickly. It might go down 2 gears in order to maintain speed. This is more prevelant when using cruise control.

You were dragging 20K lbs down the road and you used 6 gallons of fuel over 45 miles? 8 MPG might be a little low. But it depends upon the terrain and how fast you were trying to pull. Too fast uses a lot of fuel and too slow will as well. Gotta find the "sweet spot".

72-74 mph is the sweet spot on my 6.0/Auto/3.73 combo hauling 10K lb enclosed car hauler. The RPMs are high enough that it is on the lower edge of the torque curve to prevent frequent down shifts and low enough RPM to yield reasonable fuel economy (11-12 mpg).

Jul 11, 2007 | 11:38 PM

Cowboy Brett

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From: Wickenburg, AZ

I don't think there's any trouble with that. The fan does come on like that when you pull big loads, even more so once you tackle a grade.

It might cruise along at a lower RPM without using Tow/Haul. T/H puts the transmission shiftpoints a good deal higher and activates the engine braking routine (automatically gears down and uses the trubocharger sort of like an exhaust brake works). I've never gone up that high loadwise with mine (I bop around 10 and 15k), so it may or may not work with you.

I'm also running 3.73 axles. The sweet spot is right around 72 mph, just where mitchntx has it. I'd put the RPM range between 1800 and 2200.

Jul 12, 2007 | 08:34 PM

bigredtruckmi

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From: Huntington Indiana

http://www.trailerlife.com/output.cfm?id=42175

According to trailer life magazine the max tow load capacity for a F250 6.0 w/4:10 rear is 16500 lbs. with fifth wheel.

With your load of 19960 you was overloaded by 3460 lbs.

Last edited by bigredtruckmi; Jul 12, 2007 at 08:56 PM.

Jul 13, 2007 | 09:29 PM

cfd312

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I don't know if this matters. But the truck weighed just inder 10000 and the trailer just over 9000 so wouldn't that mean the total weight was only just over 9000 gross trailer weight. When i see that web site i see the trailer grossing out at 16500. am i making sense or am i being a little unrealistic. If i think about it since the gooseneck is on the rear axle that would still count the trailer weight of around 14000 because of the axle weight when loaded. but i don't know the axle weight of the truck when i don't have the trailer. i just know the truck weighs around 8400 with me in the truck. hope i make sense and wasn't rambling.