When do you use the tow/haul mode?

Stream 1529 · 06-13-2007, 12:58 PM

A friend of mine and I were talking about using the tow/haul mode. He says that he keeps his engaged from beginning to end. I use mine when I encounter steep grades and as an aid stopping. The rest of the time it is not engaged because I think I get better mileage because my RPMs are under 2000.

I'm curious how others use theirs and why.

__________Tom

ScottW · 06-13-2007, 01:02 PM

Tom, I recently upgraded my truck and it has T/H. I've tried it here in MS locally (mostly flat, small hills). I agree with you. In the flatlands, I find the RPM much lower with tow/haul off. In the hilly parts, it does delay the shift p oints, making the trans work better, at least for me. I intend to continue operating like this until someone smarter than me tells me why I shouldn't.

SafariSS · 06-13-2007, 01:05 PM

I have a 2500 Suburban, and the manual asks you to use it all of the time. I agree that on the flat sections of open highway, you will get better mileage out of OD, but at the risk of extra heat in the torque converter for only 1 mpg it is not worth the risk IMO.

Curiously, I only get about 2 mpg better w/o my trailer than with. I dont know whether that is a testament to the Airstream, or a negative with my Suburban.

Remember the Tow Haul mode also re-mapps your fuel delivery, shift points, timing etc.

**CanoeStream** · 06-13-2007, 01:19 PM

Ya gotta look in the manual. My old Nissan Titan had me use it pretty much all the time. My Duramax-Allison GMC says I don't need it until my tow hits 10,000 pounds (shooting from the hip -- might be off a bit). Otherwise I'd probably agree with ScottW's post above. You'll pull reasonably well either way but using tow-haul produces less stress on the drivetrain if there are any terrain challenges. Of course your right foot has a lot to do with that too. I don't think tow-haul changes much of anything when you are in top gear at highway speeds.

byamcaravanner · 06-13-2007, 01:20 PM

It's best to use T/H any time you are pulling a TT. It is set up to adjust the shift points to keep the transmission cooler. Overheating your transmission is the easiest way to ruin it. As SafariSS said... it's not worth saving a little gas.

Stream 1529 · 06-13-2007, 01:25 PM

Quote:

Originally Posted by SafariSS

I have a 2500 Suburban, and the manual asks you to use it all of the time. I agree that on the flat sections of open highway, you will get better mileage out of OD, but at the risk of extra heat in the torque converter for only 1 mpg it is not worth the risk IMO.

Curiously, I only get about 2 mpg better w/o my trailer than with. I dont know whether that is a testament to the Airstream, or a negative with my Suburban.

Remember the Tow Haul mode also re-mapps your fuel delivery, shift points, timing etc.

Ok, I've just monitored my transmission temperature gauge while towing, and it's never gotten hot when I tow using the regular transmission. I'm just going to have to use the tow mode on our next trip. So, what you are saying about the remapping stuff is that always using the tow mode is better for the engine and transmission?

When I'm on the highway, sans trailer, I average over 20 mpg at 60 mpg. Towing, I get anywhere from 10-14 depending on all variables.

Silvertwinkie · 06-13-2007, 01:31 PM

I have a 3/4 ton Burb too and use tow/haul when on the road towing all the time. I have yet to see and RPM increase due to tow haul on flat land at 55mph or faster. I do note that it shifts later and can hold the RPMs while in the lower gears, say 2nd, but after 40mph, it shifts to the next gear, then the final OD gear. What tow/haul does is keep the trans from overshifting when you come to smaller hills, etc. FWIW, I have 4.10s in the back.

HiHoAgRV · 06-13-2007, 02:06 PM

The '06 Dodge TD TOW button seems to upshift shift at the same time, but it keeps the converter engaged almost to a full stop, I guess to assist in slowing. It also seems to stop the downshifting until it can't torque any more and with 600+ftlbs of torque, thats a low rpm. I use it all the time 'cause everything is shifted and locked in by 50 mph anyway. I have never used the OD lockout.

SilverRanger · 06-13-2007, 02:14 PM

It's pretty flat where I live, so I rarely use it when local. When towing on mostly flat roads the tach is usually at 1600-1800 without tow/haul. When I engage the tow/haul it raises to 2000-2100 RPM, so I use it selectively. But when traveling where it's mostly hilly I use the tow/haul constantly. This is the first vehicle I've had with tow/haul and I like how it works.

LI Pets · 06-13-2007, 02:30 PM

The rpms do play games on the flats.

What I found is it doesn't shift in to 6th or high gear until I hit 68-70 mph.

What I do is click it off it will shift into sixth the rpms drop to 1800 or so at 65-68mph, now I hit the TH mode all is perfect.

The most important use of TH mode is going down hills and braking, I think If my TT brakes failed I would stop within 90% of the distance, I love it!

Fyrzowt · 06-13-2007, 02:44 PM

The manual says use it when towing or hauling a significant load.
I do.
Dave

BillTex · 06-13-2007, 02:51 PM

From 06 DA Manual;
Tow/Haul Mode
Tow/Haul is a feature on automatic transmission
equipped vehicles that assists when pulling a heavy
trailer or a large or heavy load. See Tow/Haul Mode on
page 2-30 for more information.
Tow/Haul is designed to be most effective when the
vehicle and trailer combined weight is at least 75% of
the vehicle’s Gross Combined Weight Rating (GCWR).
See “Weight of the Trailer” later in the section.
Tow/Haul is most useful under the following driving
conditions:
• When pulling a heavy trailer or a large or heavy
load through rolling terrain.
• When pulling a heavy trailer or a large or heavy
load in stop and go traffic.
• When pulling a heavy trailer or a large or heavy
load in busy parking lots where improved low
speed control of the vehicle is desired.
Operating the vehicle in Tow/Haul when lightly loaded
or with no trailer at all will not cause damage. However,
there is no benefit to the selection of Tow/Haul when
the vehicle is unloaded. Such a selection when unloaded
may result in unpleasant engine and transmission
driving characteristics and reduced fuel economy.
Tow/Haul is recommended only when pulling a heavy
trailer or a large or heavy load

FWIW; I put on T/H just before I drop it on the ball. It stays on untill I jack it back up...
Use it-that's why it is there!
Bill

rickandsandi · 06-13-2007, 02:52 PM

Whenever my Aistream is hooked-up to our Tahoe we are in Tow Mode and in 3rd gear. Cruise along just fine and average 12 MPG. Also never use cruise control.

Stream 1529 · 06-13-2007, 02:59 PM

Quote:

Originally Posted by SilverRanger

It's pretty flat where I live, so I rarely use it when local. When towing on mostly flat roads the tach is usually at 1600-1800 without tow/haul. When I engage the tow/haul it raises to 2000-2100 RPM, so I use it selectively. But when traveling where it's mostly hilly I use the tow/haul constantly. This is the first vehicle I've had with tow/haul and I like how it works.

This is why I haven't used mine all the time. Unless I have a small grade to climb, I'm always under 2000 RPM, and I figured the engine, tranny and torque converter were not over stressed. Plus, my mpg is better under 2000 RPM.

From the other posts however, this may not be the case. I may be causing everything to be overworked by not using the TH mode all of the time. I'm going to try towing in TH on our next trip and see what the difference is. Another question is does fuel efficiency have any bearing on how affectively everything is operating? To the non-skilled, it would seem that if the engine isn't being over worked, and is using less fuel then everything is fine. That's the answer I'm looking for - I think.