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07-05-2020, 10:33 AM
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#1
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Senior Member
Join Date: Jan 2020
Location: On the Road
Posts: 651
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Tow/Haul
Hi All,
So my truck (see signature) has tow/haul mode. I have always used it when towing. My understanding is it will shift less using a higher RPM (in a nutshell).
Now that I am a full timer on the road I am learning a lot of things.
I noticed my mileage was really bad! Like 8 MPG, and just drinking the DEF like crazy. Some of this was due to some headwinds, hate the wind. Anyway, stopped to fuel up and got back on the road. I forgot to turn tow/haul back on. And guess what? My mileage was up and staying between 12 - 14 MPG. That is a big difference! The RPM's were lower. Nothing was running any hotter than usual (tranny/oil) it wasn't shifting any different either. And it stopped gulping the DEF.
So I am going to run without if for now, I will use if for any long uphill grades.
What do you guys think? Do you use it (if you have it)?
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07-05-2020, 10:43 AM
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#2
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Senior Member
Join Date: Mar 2019
Location: Brunswick Hills
Posts: 906
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My Titan has a tow mode switch. I have no idea as to the similarity to yours, however, what it does for me is change the shift points of the first three gears. Above those, no difference. The shift points are higher in rpm's than when not selected.
Now, that said, if I'm in the east coast mountains, my truck drinks gasoline at a rate that scares me because of lower gears being selected on grades. Out of the mountains, very little difference between towing and not towing....maybe 2mpg difference. I attribute that to so few downshifts when at speed. So my guess is that if you're hitting a lot of inclines with tow mode on, you should see more fuel burned due to higher rpm's being invoked before the next gear is selected.
__________________
Experience is what you get when you don't get what you want.
"We'll be friends until we're old and senile,....then we'll be new friends."
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07-05-2020, 10:50 AM
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#3
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Senior Member
Join Date: Dec 2017
Location: RV
Posts: 892
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I'm all for lower rpm's and better fuel mileage, but I'm not for straining my transmission to death. That's why I tow only in tow/haul.
__________________
Full Time RVing
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07-05-2020, 11:18 AM
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#4
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Senior Member
Join Date: Jan 2020
Location: On the Road
Posts: 651
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Quote:
Originally Posted by Riverman
I'm all for lower rpm's and better fuel mileage, but I'm not for straining my transmission to death. That's why I tow only in tow/haul.
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How is it straining it if it isn't running any hotter or shifting more than when in tow/haul?
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07-05-2020, 11:25 AM
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#5
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Senior Member
Join Date: Dec 2017
Location: RV
Posts: 892
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I treat my truck gently, it has to last as long as I do.
__________________
Full Time RVing
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07-05-2020, 11:30 AM
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#6
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Site Team
Join Date: Apr 2012
Location: Newark, NY
Posts: 15,767
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We use it every time we hook up the trailer...which I remember to do MOST of the time. Besides it changing a vehicle's transmission shift patterns, it also changes the shift points, your transmission probably will downshift earlier to help you slow down, and might disengage the vehicle's overdrive, depending on the make. It seems to keep the engine in the torque curve, and towing up hills seems easier. Yes, we burn a little more gas, but all in all, I believe it causes less tranny stress.
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Moderator
Think you're too old to cry or swear out loud...walk into your hitch in the dark.
2012 Jay Flight 19RD
2016 Ford F150 XLT 2X4 SC 3.5L Eco Max Tow
2010 Tundra TRD DBL Cab (Traded)
2 new fluffy Corgis, Bayley and Stanley
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07-05-2020, 11:31 AM
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#7
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Senior Member
Join Date: Jan 2020
Location: On the Road
Posts: 651
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Quote:
Originally Posted by Riverman
I treat my truck gently, it has to last as long as I do.
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So do I! That's why I am asking.......How is it straining it if it isn't running any hotter or shifting more than when in tow/haul?
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07-05-2020, 11:36 AM
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#8
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Senior Member
Join Date: Dec 2017
Location: RV
Posts: 892
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As above, less strain and stress.
I will say this.... if it were not recommended then Chevy, Ford and Dodge would not put it on the trucks.
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Full Time RVing
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07-05-2020, 11:42 AM
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#9
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Member
Join Date: Jun 2020
Location: Winchester
Posts: 83
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The tow mode usually operates in 2 different ways. Some change the shift point so there's less hunting for gears and some act like an overdrive and prevent you from going in the highest gear. Either way if your transmission is hunting up and down for gears you should use it.
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07-05-2020, 11:47 AM
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#10
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Site Team
Join Date: Apr 2012
Location: Newark, NY
Posts: 15,767
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snip...
Quote:
Originally Posted by Spower
How is it straining it if it isn't running any hotter or shifting more than when in tow/haul?
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Your 3500 with a diesel has a ton of torque, and you may not notice any difference in or out of tow mode. In your instance, the truck is pulling your rig just fine, as indicated by the temperature gauges. If you want the transmission to help on a long or steep downhill, you can engage it then. It's a personal preference whether to use it or not, depending on the size of the RV, and what's powering the truck. We have a Ford 3.5 V6, so we use it. Conversely, my BIL tows a bigger TT with a GMC Duramax/Allison, and doesn't feel it's necessary. His truck, and his choice.
__________________
Moderator
Think you're too old to cry or swear out loud...walk into your hitch in the dark.
2012 Jay Flight 19RD
2016 Ford F150 XLT 2X4 SC 3.5L Eco Max Tow
2010 Tundra TRD DBL Cab (Traded)
2 new fluffy Corgis, Bayley and Stanley
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07-05-2020, 02:26 PM
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#11
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Senior Member
Join Date: Jun 2010
Location: Saskatoon Sask Canada
Posts: 10,714
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Quote:
Originally Posted by Spower
Hi All,
So my truck (see signature) has tow/haul mode. I have always used it when towing. My understanding is it will shift less using a higher RPM (in a nutshell).
Now that I am a full timer on the road I am learning a lot of things.
I noticed my mileage was really bad! Like 8 MPG, and just drinking the DEF like crazy. Some of this was due to some headwinds, hate the wind. Anyway, stopped to fuel up and got back on the road. I forgot to turn tow/haul back on. And guess what? My mileage was up and staying between 12 - 14 MPG. That is a big difference! The RPM's were lower. Nothing was running any hotter than usual (tranny/oil) it wasn't shifting any different either. And it stopped gulping the DEF.
So I am going to run without if for now, I will use if for any long uphill grades.
What do you guys think? Do you use it (if you have it)?
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Use tow/haul on the downhills too.. it helps with braking..
you really only need tow/haul IF the tranny starts hunting for a gear.
__________________
Seann
2004 Chev Silverado Duramax optioned past the max. 2009 Jayco Eagle 308 RLS 900watts of solar, Lithium batteries (400amp hour), 2000 watt (4000 surge) whole house inverter.
145days boondockinig in2023 2022/151 2021[/COLOR]
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07-05-2020, 02:32 PM
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#12
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Senior Member
Join Date: Jun 2016
Location: Newburgh
Posts: 6,307
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I use it in my F250 almost all the time however there are times where the truck will downshift to a gear I feel is way to low and drive the rpm's way too high for my liking. I also will manually lock out 6th gear when I do use tow / haul mode...
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2022 33RBTS
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07-05-2020, 05:38 PM
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#13
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Senior Member
Join Date: Jan 2020
Location: On the Road
Posts: 651
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My truck has exhaust braking for downhills, way better than using the transmission
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07-05-2020, 06:09 PM
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#14
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Senior Member
Join Date: Oct 2019
Location: Phoenix
Posts: 3,829
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I have had two Duramax diesels and now this E450 (only because I could not find a class C in the size I wanted with a Duramax ) in every case the Tow/Haul mode kept the vehicle from becoming a rocket while going down long steep grades. That is what that mode is designed to do. It also keeps the transmission from going nuts shifting up and down with every little change in grade.
I never really saw much difference in fuel mileage one way or another but I did see a major change in shifting and speed down hill so if you want to save a few cents in fuel at the expense of the engine, transmission and your down hill safety go for it but it is there for a reason.
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07-05-2020, 06:10 PM
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#15
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Senior Member
Join Date: Oct 2019
Location: Phoenix
Posts: 3,829
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Quote:
Originally Posted by Spower
My truck has exhaust braking for downhills, way better than using the transmission ��
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Exhaust braking works in conjunction with tow/haul, at least with Duramax.
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07-05-2020, 07:20 PM
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#16
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Senior Member
Join Date: Jan 2020
Location: On the Road
Posts: 651
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Quote:
Originally Posted by CAG
I have had two Duramax diesels and now this E450 (only because I could not find a class C in the size I wanted with a Duramax ��) in every case the Tow/Haul mode kept the vehicle from becoming a rocket while going down long steep grades. That is what that mode is designed to do. It also keeps the transmission from going nuts shifting up and down with every little change in grade.
I never really saw much difference in fuel mileage one way or another but I did see a major change in shifting and speed down hill so if you want to save a few cents in fuel at the expense of the engine, transmission and your down hill safety go for it but it is there for a reason.
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Mine is not a duramax, and does NOT act the way you described yours does. My transmission does not go nuts shifting up and down.
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07-05-2020, 07:31 PM
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#17
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Senior Member
Join Date: Jan 2020
Location: On the Road
Posts: 651
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So I made this post letting you know an observation with my truck and just asked what you guys do.
For those of you answering with basically saying well if you want to tear up your tranny go ahead, is being pretty nasty to me. Do you think that's what I want to do? I am female trying to learn all of this and to do the right thing.
So if you can't answer with a WHY I should or should not run with or without tow/haul in a nice way, then don't bother.
Thank you to those of you that have.
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07-05-2020, 07:38 PM
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#18
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Senior Member
Join Date: Dec 2017
Location: RV
Posts: 892
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From GM: Tow/Haul mode adjusts the transmission shift pattern to reduce shift cycling, providing increased performance, vehicle control, and transmission cooling when towing or hauling heavy loads.
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Full Time RVing
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07-05-2020, 07:59 PM
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#19
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Senior Member
Join Date: Jul 2017
Location: Tucson
Posts: 661
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Quote:
Originally Posted by Spower
So do I! That's why I am asking.......How is it straining it if it isn't running any hotter or shifting more than when in tow/haul?
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What you’re towing isn’t that big, but you risk burning up the clutch pack in your torque converter. Tow/haul insures your torque converter is all the way locked up.
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2018 Dodge RAM 2500 / Cummins 6.7 Turbo Diesel
2018 White Hawk 28RL
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07-05-2020, 08:15 PM
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#20
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Senior Member
Join Date: Oct 2019
Location: Phoenix
Posts: 3,829
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Quote:
Originally Posted by Spower
Mine is not a duramax, and does NOT act the way you described yours does. My transmission does not go nuts shifting up and down.
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It really does not matter whether it is a Duramax or not the results will be the same. What we are all trying to tell you is Tow/Haul is there for a reason. Take the advice for the instruction it is intended. If you don’t like it fine, do as you please but you came here for suggestions and got that.
And as to going nuts shifting up and down, pay attention to the shifting in and out of tow/haul. You may be surprised at the difference.
As was said, it is there for a reason. It would not be there if it did not have a purpose.
And the WHY is, you will eventually damage you transmission.
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