When do you use the tow/haul mode?

[SilverGate]

I agree with ROBERTSUNRUS, post #29.
(BTW, Thanks, Bob, for your input on the Equal-i-zer Question, post#37, of the thread:
http://www.airforums.com/forums/f464/equalizer-question-32805-3.html,
Page 3.)

I also agree with BillTex, post #35. (BTW, Thanks for telling us how you corrected the Equal-i-zer incorrect installation problem, post #32, of the thread:
http://www.airforums.com/forums/f464/equalizer-question-32805-3.html

I, also drive the F-250 PSD with the Tow/Haul feature engaged most of the time when pulling the 23’ Safari. I, also, completely agree with BillTex’s preferred towing speed of 62-63 mi./hr!

[ROBERT CROSS]

so what do ya do; try to keep everyone happy.<><> or use the caps and hope others will understand<><>not all of us are 20/20..

[hiker]

Originally Posted by BillTex

I am also well under the 75% for the D/A, but I find the engine grade brake feature invaluable so I leave TH on whenever I am hooked up.
I have experimented towing with the truck in TH and without at our usual towing speed (62-63mph) and the result is no difference in RPM or MPG so I go for the engine braking and just leave TH on.
If I towed faster maybe I would see some advantage in dropping the TH mode at speed, as far as RPM or MPG, but I am not really comfortable towing faster than 62/63 with a load behind me and my family in the truck, so it has not been an issue. I don't want to start the "speed" debate again, but in this part of the woods (New England), anything faster while towing is nuts...

I tow at about 60 mph, sometimes up to your 62-63 mph, but never faster. What I said in my post was: " ... have towed in +90 weather with transmission temp staying well within normal limits."

To avoid any possibility of ambiguity, perhaps I should have said "+90 degree weather." I don't think I would have said "anything faster while towing is nuts...", but we agree about towing speed.

Why would you want to sacrifice engine braking and not use TH?

I don't like the increased RPM and resulting increased engine noise caused by the delayed shift points. I don't feel I am sacrificing engine braking because I use T/H mode on hilly/mountainous (rolling terrain).

[ROBERTSUNRUS]

Originally Posted by ROBERT CROSS

so what do ya do; try to keep everyone happy.<><> or use the caps and hope others will understand<><>not all of us are 20/20..

Hi, ROBERT CROSS. You are about three years older than me [if that makes any difference] and I don't have 20/20 vision either. When you type your next post you can click on the "down arrow" next to the "2" and change the size to a "4" like this is, but this won't help you that much unless everyone does this.

If you do use caps, anyhow, the moderators will put you on warning and eventually not let you post.

[LI Pets]

Boy, look what I started

All you need to do is go to the tool bar on your browser and look for "text size" and pick a larger size.

Then you will see all posts clearly!

[LI Pets]

Originally Posted by hiker

I tow at about 60 mph, sometimes up to your 62-63 mph, but never faster.

So you're the guy I almost rear ended

I don't like the increased RPM and resulting increased engine noise caused by the delayed shift points. I don't feel I am sacrificing engine braking because I use T/H mode on hilly/mountainous (rolling terrain).

Mike, I disagree that you aren't sacrificing braking on flat roads, at all!

Do a measured hard stop, you will stop in less distance.

Do it in TH and then do it again from the same starting point at 55Mph

Stopping in less distance = no crash

Ps: If you don't like the increased RPM and resulting increased engine noise caused by the delayed shift points,

Just pop out of TH till you reach speed then pop it back in so you can stop better and safer.

[CanoeStream]

For the record -- AIR Forums posts have a fairly homogenous look. It is felt that this is easier to read and follow. Toward that end the moderators may make changes if it is judged that there is unwarranted bolding, changing font size, using excess color ... and yes, caps. IMO, none is being used in excess here nor is it being used to drive a point against another member (thus not crossing the firmer 'no shouting' barrier, Bob 1).

Interpretation of this matter is so minor that we don't aim toward consensus & inner mod discussions. Uniformity is not possible, so what one mod might allow could be returned to size 2 Verdana by another.

I return you to the good thread already in progress...

[moosetags]

We use the tow/haul mode on our 2500 Suburban at all times when towing Lucy.

[Pick]

I use mine quite frequently when NOT towing in city traffic. Keeps the trans temperature lower and minimizes the use of brakes.

[Minnie's Mate]

One thing I didn't post in my lengthy post (my wife tells me my story is too long all the time ) is that the PSD transmission (Don't know who makes it ) has six gears but only uses five of them in either mode. In regular mode, I think it skips #4. In Tow/Haul is uses #4, but skips #5 in addition to modifying the shift points. I really am not sure about which gears are skipped in which mode so don't quote me.

[hiker]

Originally Posted by LI Pets

So you're the guy I almost rear ended



Mike, I disagree that you aren't sacrificing braking on flat roads, at all!

Do a measured hard stop, you will stop in less distance.

Do it in TH and then do it again from the same starting point at 55Mph

Stopping in less distance = no crash

Ps: If you don't like the increased RPM and resulting increased engine noise caused by the delayed shift points,

Just pop out of TH till you reach speed then pop it back in so you can stop better and safer.

Have you done this experiment? I can understand how engine braking can reduce brake wear and tear and possible fade on long descents, but it is surprising to me that it would have much effect, if any, once the truck and trailer brakes are fully engaged as in a panic stop. Assuming the brakes don't fade, I would have thought the limiting factor in stopping ability is tire friction (i.e. preventing the wheels from locking up). Isn't that what anti-lock brakes are all about?

If my intuition is wrong about this, you make a very good point.

[Stream 1529]

This is what I've been using it for. A diesel enging does not retard when you take your foot off of the accelerator, it just coasts along. When you use TH, the diesel will retard just like a gasser, and helps to decrease your speed.
Of course if you need to slow down faster, applying the brakes in TH will cause your transmission to downshift slowing the trailer with minimal assistance from the brakes. In an emergency stop the transmission and brakes should stop your rig in a shorter distance when using TH.

________Tom

[Swanny]

With my '05 F-350 I use it whenever I tow our AS. I originall bought into the thought process that the lower the RPMs the better the fuel economy; however during my last 4 trips this was proven wrong.

We have a diesel and I've noticed that when in the Tow/Haul mode it changes the motor into a brake as well. By this I mean that the engine helps slow down the vehicle while braking because the truck shifts at different speeds.

We made an 800 mile round trip to Dallas 2 weeks ago and averaged 16 MPG towing our 34 Excella.

Mitch

[Minnie's Mate]

Originally Posted by Swanny

We made an 800 mile round trip to Dallas 2 weeks ago and averaged 16 MPG towing our 34 Excella.

Mitch

Wow! That's impressive. My 30' Safari weighs just about 6,500 # dry and I get about 12.2- 12.6 towing in the Tow/Haul mode at interstate speeds. I haven't weighed it loaded, but I'm sure it isn't as much as your Excella.

[bhayden]

With our little Safari van pulling a 4,000# Argosy I try to use TH all the time. The problem is the bassackward GM engineers decided that it would be smart to reset to normal mode every time you shut off the engine so it's easy to forget to switch it back on (they also swipe the wipers every time you decrease the time delay or turn them off ). I also use TH in the mountains even if I'm not towing; the quicker downshifts really help; especially if you're trying to use cruise control. Of course I don't use cruise in the mountains when I'm towing.

[ROBERTSUNRUS]

Hi, for some of us who don't have tow/haul modes on our transmissions, I manually down shift, up and down hills, for that added power and brakeing effect. I have down shifted going down hill and have vertually gone all the way down the hill without useing [or barely useing] my brakes. Let the engine and trans help slow you down instead of burning up your brakes.

[ROBERT CROSS]

ROBERT:
I'm with you Robert, downshift when necessary, and try to keep the tranny temp below 190. No tow/haul 0n the 95 Suburban.......Bob...


KEEP STREAM'N

[AgZep]

We've done about 2,000 miles in the last two weeks. Our trailer is a 28' CCD, loaded pretty light at the moment. Our TV is a 2001 Chevy 2500HD with the 8.1 gas engine and Allison transmission.

We've been getting around 11 mpg, generally at 55 mph. We did a couple of stints at 60 mph, and a few where we slowed a bit due to construction. No noticable mileage difference in either case. I suspect the increased aero drag from going faster might be offset by the engine breathing a bit more efficiently at the wider throttle opening.

At 55 mph in T/H, the Allison will not switch down to overdrive. Once we go a little over 60, it will. So I just take it out of T/H when I'm cruising in a flat area, which will cause a shift into overdrive, then immediately turn T/H back on. That gives me the brake assist if I ever need it, without forcing the engine up 600 rpm needlessly while cruising.

I think a lot of this discussion proves that different transmissions are programmed differently, and that gas engines benefit somewhat less from brake assist than diesels.

Our truck also seems pretty insensitive to weight and speed when it comes to mileage. The best I've ever done while not towing was 17, but I typically get 13 or so.

I might have rather had a diesel in the first place, but we got our truck used from my brother in law who lives in Wyoming. At his altitude, and with the wildly variable weather out there, diesels are sometimes a problem. When we get our next truck, it will probably be a diesel (GM stopped making gas/Allison trucks anyway).

[BillTex]

Originally Posted by AgZep

I might have rather had a diesel in the first place, but we got our truck used from my brother in law who lives in Wyoming. At his altitude, and with the wildly variable weather out there, diesels are sometimes a problem. When we get our next truck, it will probably be a diesel (GM stopped making gas/Allison trucks anyway).

Hi Ag,
This is odd; typically normally aspirated (most gasoline powered truck engines on the market today) engines do poorly at higher elevation. Turbocharged (most diesel engines on the US market today) are not prone to performance loss at elevation.
Anyway, every time I am out towing with the Allison, I am just amazed at its performance. I have owned many trucks over the years (this is my first diesel) and regardless of what engine they have had, there is nothing like this Allison (that I have driven). I can’t imagine a better tool for towing. The rock solid shift patterns, engine braking, and reliability make me feel like I am driving a locomotive-towing is a pleasure with this combo; solid, stable, plenty of juice for hills, passing, etc. It is a good feeling to know when you hitch up and head out that you have such a platform to haul your family, and stuff!
You do have a point about different trannies and rear end ratios, and their effect on performance. When I am towing (62-63mph) I can pop it in/out of TH and the tach does not change at all (mpg constant also). This is a D/A with the standard 3.73:1 rear end and 6 spd Ally.

Bill

[Streamer1]

We drive an F250 PSD and use the "Tow-Haul" mode whenever we tow (and don't forget to press the button). Probably would not be a bad idea for the pickup manufacturers to have an "idiot" light (what's one more light?) that recognizes that a trailer is attached and would ask you if you would like to utilize "Tow-Haul" mode at this time.