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i have a 07 6.7l and i tow a 20k fifth wheel this truck wont pull it in sixth gear it always downshifts to fifth what can i do to get it to pull in sixth the mpg is friggin horrible :confused013:
 

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Im not a 6.7 expert, but im gonna have to say its probably a combination of heavy weight, 37 inch tires, and im not sure what gears you have, but more than likely the 37s is why it wont stay in 6th.
 

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can you put it in sixth manually with the clicker and have it tow like that once you are up to cruising speed?
 

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LOL you can't to that much weight efficiently in 6th lol.
 

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i have a 07 6.7l and i tow a 20k fifth wheel this truck wont pull it in sixth gear it always downshifts to fifth what can i do to get it to pull in sixth the mpg is friggin horrible :confused013:
First off, what gears and what tires? My 08 with 3:73 gears would pull my 18K trailer and with both trailers 22K in 6th without a problem. My 2010 just pulled my 18K trailer this past weekend without a problem in 6th gear with 3:42's.
 

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First off, what gears and what tires? My 08 with 3:73 gears would pull my 18K trailer and with both trailers 22K in 6th without a problem. My 2010 just pulled my 18K trailer this past weekend without a problem in 6th gear with 3:42's.
He said 37s
 
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i have 35s and put her in tow haul mode.. i could drag a ford assembly plant down the road in 6th
 

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i have 35s and put her in tow haul mode.. i could drag a ford assembly plant down the road in 6th
Maybe so, but with 2" taller tires, and he could have higher gears, and 18k is a good load, that sounds like making a big load harder to pull to me. With 37s i would think 4.10s would be dman near mandatory, i know with just 33s im thinking about 4.10s
 

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20k is a lot to try and move with a pickup, 2 gears up from direct.....
 

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He said 37s
Where does he say 37's? The truck in his signature is NOT the truck he is talking about. To the best of my knowledge there were no 6.7's in 2004 :D
 

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Where does he say 37's? The truck in his signature is NOT the truck he is talking about. To the best of my knowledge there were no 6.7's in 2004 :D
Aww hell, didnt even notice that:doh: I guess i get a :spank:...I appreciate that man, lol, thats all i need is somebody helping me look dumb:S:
 

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If the transmission is shifting back to 5th on its own while towing then it “sounds” like you have too much load for 6th gear. From other trucks that I’ve owned, if I was loaded and the transmission was shifting in and out of overdrive then I knew I was loaded to heavy to tow in overdrive.
Others have asked what tire size you are running. That is a good question and will make a difference when towing.

Just out of curiosity, I'm still gathering a lot of info here and the load that the transmission will handle safely is a concern to me. I have the same truck and tow a 16K Fiver.
Is it recommended to tow in 5th or 6th gear? I do use the tow/haul while towing. My last trip, I kept the tranny in 5th. MPG sure hurts like that but I don’t yet know what the transmission will handle without smoking it. I can tow in 6th gear with that weight because I did try it for about 30 miles.
 

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i imagine your fuel mileage will hurt more by lugging your motor at a lower rpm. needs to be in sweet spot of power band for peak performance. just slowing the rpn down dont cut it.
 

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i have 4.10's in my 08 and i ahve yet to see my truck downshift towing anything ive towed, but then again it i stock tires, i would swap to stock tires and see if that fixes the problem.


Im quite certain that its just to much lugging for the truck with those huge tires, and that a gear change is needed.
 

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Nobody has said he is running 37's. The truck in his signature IS NOT the truck he is having the problems with
 

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i have a 07 6.7l and i tow a 20k fifth wheel this truck wont pull it in sixth gear it always downshifts to fifth what can i do to get it to pull in sixth the mpg is friggin horrible :confused013:
If you want to use 6th, you will have to kick up your speed. How tall are your tires, and what gears are you running?
 

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You are effectively running 2.98 gears if the truck is equipped with 3.73s now. That is the reason it will not stay in 6th, with the load you are pulling. To get back to near stock you need 4.56 gears or shorter tires. The ideal tow RPM is between 1600 and 2000, this puts you in the sweet spot of the torque curve. I run mine all day long locked on cruise at 120 KPH, towing. She sits at 1900 RPM in 6th gear. It will shift down a gear on steep grades and back up to 6th. I am running 285/70/17 tires.
 

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You are effectively running 2.98 gears if the truck is equipped with 3.73s now. That is the reason it will not stay in 6th, with the load you are pulling. To get back to near stock you need 4.56 gears or shorter tires. The ideal tow RPM is between 1600 and 2000, this puts you in the sweet spot of the torque curve. I run mine all day long locked on cruise at 120 KPH, towing. She sits at 1900 RPM in 6th gear. It will shift down a gear on steep grades and back up to 6th. I am running 285/70/17 tires.
He has never stated his tire size yet. The truck in his signature is not the one he talking about.:thumbsup:
 
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