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  1. #1
    Senior Chief Petty Officer scooper77515's Avatar
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    Default What does tow/haul button do?

    I know it holds shift points to a little higher rpm, but what does it do for passing, fuel economy, etc.?

    I assume it just sucks more gas by keeping rpms up keeping the engine in a more responsive torque range.

    Any benefit to driving with it on?

    04 Dodge Ram 1500 with 5.7 Hemi 5-speed auto.
    2003 Glastron GX 185, with VolvoPenta 4.3GL, currently running Stilleto Baypro III 14.25X21 at 46 mph and 4400 rpms. Other props were 3-blade aluminum 14.3X23 at 43 mph and 4400rpm, and 14.3X21 at 49mph at 4800 rpms.

  2. #2
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    Default Re: What does tow/haul button do?

    Keeps it in a lower gear longer before upshifting and it keeps it out of 5th gear on the 45rfe trannys.
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  3. #3
    Moderator QC's Avatar
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    Default Re: What does tow/haul button do?

    It also downshifts earlier and can seemingly contradictorily hold a gear in lockup under a hard pull before downshifting longer too. Should ultimately reduce "hunting" between gears as well.

  4. #4
    Senior Chief Petty Officer scooper77515's Avatar
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    Default Re: What does tow/haul button do?

    So i should definitely have it off when cruising on flat freeways. I like the better fuel economy of 5th gear.

    So would it be beneficial for short hauls through town with lots of stop and go, or should i just leave it off?

    Hauling 18.5' glastron on steel trailer.
    2003 Glastron GX 185, with VolvoPenta 4.3GL, currently running Stilleto Baypro III 14.25X21 at 46 mph and 4400 rpms. Other props were 3-blade aluminum 14.3X23 at 43 mph and 4400rpm, and 14.3X21 at 49mph at 4800 rpms.

  5. #5
    Admiral Huron Angler's Avatar
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    Default Re: What does tow/haul button do?

    I believe it's the same as "overdrive off" on my Ford. It keeps the transmission from shifting excessively and is good when towing is what I've been told, as mentioned.

  6. #6
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    Default Re: What does tow/haul button do?

    Not sure about the mopars, but the Chevys increase the line pressure to the clutches also.

  7. #7
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    Default Re: What does tow/haul button do?

    It' is basically what was stated above. It is an electronic switch that allowes the tranny to shift at a higher rpm, or a shift point. It also keeps the tranny from "hunting gears" as this will heat up your tranny in a hurry even with a cooler, this puts alot of strain on the transmission. As far as going down the highway with it off, well that depends on the load, if your carrying a light boat or just about maxing out the trucks towing capacities. If your on the heavier side i would leave it on, and the computer will find the most comfortable gear, and it will eventually find the 5th, or top overdrive gear, if there isn't too much strain on the engine and tranny. That only applys to the tow/haul button, not the o/d off.

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  8. #8
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    Default Re: What does tow/haul button do?

    Quote Originally Posted by scooper77515 View Post
    I know it holds shift points to a little higher rpm, but what does it do for passing, fuel economy, etc.?

    I assume it just sucks more gas by keeping rpms up keeping the engine in a more responsive torque range.

    Any benefit to driving with it on?

    04 Dodge Ram 1500 with 5.7 Hemi 5-speed auto.
    I have a Quad Cab with your set up. I use it all the time when towing. I pull a 24 ft pontoon boat with Tandem wheel. .It's a must use thing. Mostly it keeps the truck out of over drive so you don't tare up the transmission. I get around 13.5 towing with it on. I keep it around 55 to 60 most of the time except when passing.Some times I use it in the city with out towing anything and my mileage is better then when not using it.

  9. #9
    Chief Petty Officer bkwapisz's Avatar
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    Default Re: What does tow/haul button do?

    Quote Originally Posted by EMC 1810SS View Post
    Not sure about the mopars, but the Chevys increase the line pressure to the clutches also.

    That makes sense; when I leave mine on without a trailer it shifts as though it has a shift-kit installed. Really slams into second and third. Also holds the shift for longer periods. Not sure about the fuel economy but I only use it when I pull heavy stuff.

  10. #10
    Moderator QC's Avatar
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    Default Re: What does tow/haul button do?

    Not the same as Ford's overdrive off. That blocks overdrive, GM changes all shift parameters.

  11. #11
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    Default Re: What does tow/haul button do?

    GM's web site says you void the transmission warranty if you tow with it off.

  12. #12
    Admiral Huron Angler's Avatar
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    Default Re: What does tow/haul button do?

    Quote Originally Posted by QC View Post
    Not the same as Ford's overdrive off. That blocks overdrive, GM changes all shift parameters.
    I knew someone would let me know I was wrong on this post

    I'm curious now, I must be in overdrive the majority of the time I'm towing because when I turn OD off, my RPM's immedietely drop or increase depending on the speed, and while towing it seems to keep the shifting to a minimum while going up or down hills.

  13. #13
    Petty Officer 1st Class '96 Charger's Avatar
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    Default Re: What does tow/haul button do?

    In my 09 Ram quad with the 4.7 and 5 speed tranny mine not only raises the shift rpm's but it also downshifts while going down hills to keep from having to ride the brakes. Also keeps the engine from straining in a gear it has no business being in while towing.

    On a sidenote, how would GM know the tranny wasn't in tow/haul while towing?

  14. #14
    Petty Officer 2nd Class Todd157k's Avatar
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    Default Re: What does tow/haul button do?

    Quote Originally Posted by '96 Charger View Post
    In my 09 Ram quad with the 4.7 and 5 speed tranny mine not only raises the shift rpm's but it also downshifts while going down hills to keep from having to ride the brakes. Also keeps the engine from straining in a gear it has no business being in while towing.
    Exactly the same on the Hemi's.

    also a little side note: If you ever want to over-ride the speed limiter on the Dodge Hemi p/u, hold the key in the start position (after the car is already running) and you'll here a "ding" in a few seconds. The speed limiter is then defeated.
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  15. #15
    Petty Officer 1st Class '96 Charger's Avatar
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    Default Re: What does tow/haul button do?

    The gubbener has it at 105. That's plenty fast

  16. #16
    Senior Chief Petty Officer scooper77515's Avatar
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    Default Re: What does tow/haul button do?

    Thanks for all the feedback...especially how to override the speed limiter
    2003 Glastron GX 185, with VolvoPenta 4.3GL, currently running Stilleto Baypro III 14.25X21 at 46 mph and 4400 rpms. Other props were 3-blade aluminum 14.3X23 at 43 mph and 4400rpm, and 14.3X21 at 49mph at 4800 rpms.

  17. #17
    Moderator QC's Avatar
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    Default Re: What does tow/haul button do?

    Quote Originally Posted by Huron Angler View Post
    I knew someone would let me know I was wrong on this post

    I'm curious now, I must be in overdrive the majority of the time I'm towing because when I turn OD off, my RPM's immediately drop or increase depending on the speed, and while towing it seems to keep the shifting to a minimum while going up or down hills.
    I could be wrong too, but I've had both recently. 2003 Ford Expedition and 2008 GMC 1500. For me the Ford button (OD Off) was just like shifting to 3 (from D) in the GMC. With the Tow/Haul button on, the GMC behaves differently from all speeds and pedal (throttle) positions.

  18. #18
    Lieutenant avenger79's Avatar
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    Default Re: What does tow/haul button do?

    ford's od off is essentially exactly the same as GM tow/haul it's the whole you can't call it what we call it thing. the ford will change the shift point and "alter" your gear ratios to increase towing and lessen hunting gears.

    you can pull in OD on a flat highway and retaing good fuel mileage. if you notice the tranny hunting for gears or going in and out of OD hit the switch. I've pulled a 26 foot camper with my 1/2 ton ford in OD and no probalem at all. I wouldn't do it through the mountains though.

  19. #19
    Lieutenant Commander NSBCraig's Avatar
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    Default Re: What does tow/haul button do?

    It not only changes the tranny but also the motors programing as well.

    Not at all like OD switch in fact completely different.
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  20. #20
    Lieutenant Commander paultjohnson's Avatar
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    Default Re: What does tow/haul button do?

    Quote Originally Posted by Todd157k View Post
    Exactly the same on the Hemi's.

    also a little side note: If you ever want to over-ride the speed limiter on the Dodge Hemi p/u, hold the key in the start position (after the car is already running) and you'll here a "ding" in a few seconds. The speed limiter is then defeated.
    Wouldnt you then grind the starter to death, as the starter gear tries to engage a allready spinning flywheel ?
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  21. #21
    Lieutenant Commander paultjohnson's Avatar
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    Default Re: What does tow/haul button do?

    I believe one of the bigger benefits is keeping the engine and tranny cooler by not lugging both by running in too high of gear.
    86 THUNDERCRAFT LEGACY 18 FT MERCRUISER 4.3 2 BBL 185 HP ALPHA 1 GET IN, SIT DOWN, SHUT UP, HOLD ON !!! TOW RIG 01 CHEVY SILVERADO STD CAB LONG BOX 4X4 5.3 Z71

    GO NAVY!!! USS MERRILL DD 976- SPRUANCE CLASS DESTROYER- ONBOARD 81-85 INTERIOR COMMUNICATION ELECTRICIAN PO 3RD CLASS- TEST SHIP FOR THE TOMAHAWK CRUISE MISSILE. NAS KEFLAVIK ICELAND 86-87

  22. #22
    Petty Officer 1st Class Josh P's Avatar
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    Default Re: What does tow/haul button do?

    Quote Originally Posted by paultjohnson View Post
    Wouldnt you then grind the starter to death, as the starter gear tries to engage a allready spinning flywheel ?
    new vehicles have a seperate relay for the starter solenoid, once the engine is running the pcm will not let the relay engage to prevent idiots from trying to start the vehicle while its running, and it also serves as a anti theft it wont let it crank if the vtd is enable. to the op i have an 04 qc 4x4 hemi 1500 as well. mine seems not to hold certain gears to long but feels way more torquey, i think i read on the dodge forum some where that the trans 5-45rfe has a dual stage locking torque converter and it locks half to reduce converter slippage in tow/haul mode, slippage creates heat. havent used mine much yet keep me posted. i did notice it will shift into 5th gear but it holds forth, watching for engine load to decrease.

  23. #23
    Lieutenant Commander 109jb's Avatar
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    Default Re: What does tow/haul button do?

    On a GM, tow/haul and OD are different. My GMC duramax truck has both. At least on my truck, the OD just doesn't let the transmission shift into overdrive. Tow/haul modifies upshift and downshift points, provides engine braking assistance and keeps the torque converter locked longer. On my truck you can turn on one or the other or both at the same time. I only regularly use the tow/haul mode and I use it all the time when towing any trailer over about 4000 pounds (12000 pound tow rating).
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  24. #24
    Lieutenant Commander paultjohnson's Avatar
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    Default Re: What does tow/haul button do?

    Quote Originally Posted by Josh P View Post
    new vehicles have a seperate relay for the starter solenoid, once the engine is running the pcm will not let the relay engage to prevent idiots from trying to start the vehicle while its running, and it also serves as a anti theft it wont let it crank if the vtd is enable. to the op i have an 04 qc 4x4 hemi 1500 as well. mine seems not to hold certain gears to long but feels way more torquey, i think i read on the dodge forum some where that the trans 5-45rfe has a dual stage locking torque converter and it locks half to reduce converter slippage in tow/haul mode, slippage creates heat. havent used mine much yet keep me posted. i did notice it will shift into 5th gear but it holds forth, watching for engine load to decrease.
    Huh, Really, No chit? Wow I learned something today, Thnks for the explaination
    86 THUNDERCRAFT LEGACY 18 FT MERCRUISER 4.3 2 BBL 185 HP ALPHA 1 GET IN, SIT DOWN, SHUT UP, HOLD ON !!! TOW RIG 01 CHEVY SILVERADO STD CAB LONG BOX 4X4 5.3 Z71

    GO NAVY!!! USS MERRILL DD 976- SPRUANCE CLASS DESTROYER- ONBOARD 81-85 INTERIOR COMMUNICATION ELECTRICIAN PO 3RD CLASS- TEST SHIP FOR THE TOMAHAWK CRUISE MISSILE. NAS KEFLAVIK ICELAND 86-87

  25. #25
    Petty Officer 2nd Class bobkyle2's Avatar
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    Default Re: What does tow/haul button do?

    Quote Originally Posted by Todd157k View Post
    Exactly the same on the Hemi's.

    also a little side note: If you ever want to over-ride the speed limiter on the Dodge Hemi p/u, hold the key in the start position (after the car is already running) and you'll here a "ding" in a few seconds. The speed limiter is then defeated.
    i wonder if the 08 fords are like this... i would like that option sometimes
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