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Discussion Starter #1
came across some info here,that the tow/haul mode is kinda like a sport mode button.What perimiters does it change?Any changes with an auto and its shifts points.Is it safe to run it all the time?
 

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Khaki Nitro Nut
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Tow haul just prevents it from going into OD, as far as I know. But then again I have the manual trany... lol
 

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Scar O is correct. from all my knowledge it just locks out the trans from going into OD when towing this is a good thing or else the trans would be shifting gears all the time (slipping) as well as keeping your RPM's a little higher... as for using tow/haul all day every day there is nothing saying not to but here is the down side then you only have essentially a 3 speed auto second fuel mileage will suffer due to the higher rpm's..... hope that helps you out.
 

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Discussion Starter #4
Thanks for the info guys,my auto trans in the Nitro acts very much like a 700r trans in a vette I had,To me it seems to want to shift to early,goes into over drive and then is kinda boggy.I played around with it on the way to work this morning.Feels way better to run in tow/haul mode till you get to 50-55mph then hit it and let over drive kick in.Very much like the 700r,same thing that was run in D till the 50mph mark came then shifted it in over drive.Its def more peppy in this mode:Racing:
 

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It likely also changes the shift map so it will stay in gear a little longer (higher rpm) before shifting. which would be why it seems peppier... max torque on the 3.7l is @4000rpm, and we rarely see that rpm in day to day driving.
 

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Discussion Starter #6
It likely also changes the shift map so it will stay in gear a little longer (higher rpm) before shifting. which would be why it seems peppier... max torque on the 3.7l is @4000rpm, and we rarely see that rpm in day to day driving.
That`s good info to know,So it seems out auto equipped Nitro`s are down tuned......for the sake of fuel economy?
 

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So it seems out auto equipped Nitro`s are down tuned......for the sake of fuel economy?

That would be a big....YES!
 

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Discussion Starter #8
So it seems out auto equipped Nitro`s are down tuned......for the sake of fuel economy?

That would be a big....YES!
Ah man,I hate when manufactures do stuff like that.Many vehicles have suffered from this irrational thinking.ex 1984 corvette w/ cross fire injection,intake manifold ports were only 3/4 of the size the could have been....power was cut immensely because of this....and why?So the next year tpi injection was first introduced would "prove" to have big hp numbers increase.Marketing at its best/worse I guess:rolleyes:
 

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Yes. "Tow/Haul" is basically an OD lockout. Very useful in mountain country (I live in western NC, the end of the state with mountains in it) and it keeps the transmission from constantly shifting between 3rd and 4th while going up long uphill stretches.
 

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I did confirm (personaly) that it holds gears somewhere between 500-1000rpm longer than normal. I doubt it totally cuts out the OD. If I were to guess it would wait until atleast 55 or 60mph, then engage OD. I'll see if it eventually engages on the highway and report back.
 

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on my 2010 jeep liberty sport with the 3.7 it locks out the "Over Drive" it seems similar to the way my 2004 Dodge Ram was set up. yes it does bump up the rpm's for each gear....
 

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As per the manual and much experience .
In tow haul OD is not available.

I tow a trailer.
Runs great in tow haul with higher RPM in third.
If I forget to place it in Tow haul, there is not enough power to maintain speed when the OD kick in.
Feels like you are losing power.
 

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Yep i tried and it doesn't kick in on the highway. The RPM gets too high for my liking to run constantly @65 I'd probably only go 55mph or so. Ofcourse synthetic oil would be a good thing for an engine that was going to be running like that for long.
 

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Synthetic oil would help but so would all fluids like transmission and transaxial as well. I would also suggest a transmission cooler.
 

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I believe all 3.7ls have a transmission cooler (attached to the AC condenser). I think the 4.0l have the same.

As far as I know atf +4 is a synthetic standard. Anyone know if the differential fluid is synthetic from the factory?
 

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Not sure if this question belongs here or not, but I searched and can't find a thread specific to it. So the 3.7 has a tow/haul mode, my 4.0L doesn't have that but does have the autostick. So should I be shifting it myself when I'm towing? Or can I just leave it in auto and that would be okay? I'm only hauling brush, etc. to the transfer station here in town about 10 miles away.
 

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Agree it removes the OD and bumps up the RPMs so the tranny is working less.

Once I hit highway speeds and anticipate running at those speeds for periods of time I take the Tow/Haul off as no sense running that long at high RPM's /burning gas once you hit cruising speeds. of course, hilly/mountainous terrain would be a different story.

.
 

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Khaki Nitro Nut
07Lifted,4X4,6sp-man,3.7L
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Not sure if this question belongs here or not, but I searched and can't find a thread specific to it. So the 3.7 has a tow/haul mode, my 4.0L doesn't have that but does have the autostick. So should I be shifting it myself when I'm towing? Or can I just leave it in auto and that would be okay? I'm only hauling brush, etc. to the transfer station here in town about 10 miles away.
For what you are doing auto is fine, unless the road is very hilly. If you were towing a heavy load long distance, I would suggest using the auto-stick.
A good rule of thumb is, if you drop 10 Mph, downshift.
 

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The Univalent Radical
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I just rented a Penske E350 16' Box truck and towed a Chevy Cobalt on a flat bed trailer from Indiana to Maine. They insisted I use the tow/haul, but I chose not to. If I engaged the tow/haul, the transmission never shifted out of 3rd. So, 4th and 5th must be OD on this transmission. I chose not to use it as I was only getting about 8 - 9 mpg. If the mountains were long and high in PA, then I did engage it. I never used it on my Commander with the 4.7. I think it would be wise to use it, if the transmission is constantly hunting: to prevent overheating.

:cool:
 

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Thanks for the info guys,my auto trans in the Nitro acts very much like a 700r trans in a vette I had,To me it seems to want to shift to early,goes into over drive and then is kinda boggy.I played around with it on the way to work this morning.Feels way better to run in tow/haul mode till you get to 50-55mph then hit it and let over drive kick in.Very much like the 700r,same thing that was run in D till the 50mph mark came then shifted it in over drive.Its def more peppy in this mode:Racing:
You really don’t want it in OD while pulling anything other than an empty trailer, best to just let it do what it’s designed for it’ll save ur transmission but burn more fuel
 
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